List of Posters

Author(s): Wieland Dietrich (1), Sandeep Kumar (2,3), Anna Julia Poster (4), Martin French (4), Nadine Nettelmann (5), Ronald Redmer (4), Johannes Wicht (1)

Affiliation: (1) Max Planck Institute for Solar System Research, Goettingen, Germany, (2) Center for Advanced Systems Understanding (CASUS), Görlitz, Germany, (3) Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany, (4) Universität Rostock, Institut für Physik, Rostock, Germany, (5) Deutsches Zentrum für Luft- und Raumfahrt, Institut für Planetenforschung, Berlin, Germany

Abstract:

The small semi-major axes of Hot Jupiters lead to high atmospheric temperatures of up to several thousand Kelvin. Despite being compositionally quite rare, under these conditions thermally ionized metals provide a rich source of free electrons and ions and thus build up a sizeable electrical conductivity. Subsequent electromagnetic effects, such as the induction of electric currents, ohmic heating, magnetic drag or the weakening of zonal winds have thus far been considered mainly in the framework of a linear, steady-state model of induction. Here we show that for Hot Jupiters with a radiative equilibrium temperature Teq > 1500 K, the rapid induction of atmospheric magnetic fields is a runaway process that can only be stopped by non-linear feedback. For example, the back-reaction of the magnetic field onto the flow via the Lorentz force or the occurrence of magnetic instabilities. Moreover, we discuss the possibility of self-excited atmospheric dynamos. Our results suggest that the induced atmospheric magnetic fields and electric currents become independent of the electrical conductivity and the internal field, but instead are limited by the planetary rotation rate and atmospheric wind speed.

As an explicit example, we characterize the magnetic induction process for the hottest detected Hot Jupiter, KELT-9b, by calculating the ionization degree and electrical conductivity along atmospheric p-T-profiles for the day- and night-side. Despite the temperature ranging between 3000 K and 4500 K, the resulting electrical conductivity attains an elevated value of roughly 1 S/m throughout the atmosphere. The induced atmospheric magnetic fields are predominately horizontal and might reach up to a saturation field strength of 400 mT, exceeding the internal field by two orders of magnitude.

Author(s): Eleftheria Sarafidou (1), Oliver Gressel (1), Giovanni Picogna(2), Barbara Ercolano(2)

Affiliation: (1)Leibniz Institut für Astrophysik Potsdam, (2) Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-Universität München

Abstract:

Understanding the evolution of the planet forming inner regions of circumstellar disks is one of the most prominent astrophysical problems. There are two fundamental drivers of disk evolution, which will ultimately lead to the dispersal of the disk on timescales comparable to the observational constraints. The first is photoevaporation (see, e.g., Alexander et al. 2013; Ercolano and Pascucci 2017) i.e., the dispersal of protoplanetary disks (PPDs) via winds driven by thermochemical heating -through X-rays, extreme/far-ultraviolet radiation (EUV/FUV) driven winds that are primarily associated with mass loss. The second driver is accretion of the disk material onto the central star through the redistribution of angular momentum (see, e.g.,Königl and Salmeron 2010; Turner et al. 2014; Frank et al. 2014). Additionally, when considering the detailed ionization structure in the inner regions of PPDs, it is clear that the three non ideal magnetohydrodynamic (MHD) effects have to be taken into account. Large stretches of the disk are expected to remain laminar due to the combined dissipative effect of ambipolar diffusion and ohmic resistivity (Bai and Stone 2013; Bai 2013), whereas in regions where the Hall effect is dominant, the Hall-shear instability can nevertheless amplify large-scale horizontal magnetic field and provide a means for non-turbulent accretion.
We are producing computer models of the inner regions of PPDs, by extending the non-ideal MHD model of Gressel et al. 2020, taking into account radiative, thermodynamic and non-ideal magnetohydrodynamic aspects simultaneously. We perform global axisymmetric RMHD simulations of combined photoevaporative (including X-ray and FUV) and magnetocentrifugal disk outflows, including a self-consistent temperature and ionization structure parametrization (Picogna et al. 2019). The mass outflow and accretion rates of the models are examined, as well as the evolution of the poloidal magnetic field lines threading the disk.

Author(s): Gabriele Morra (1), Leila Honarbakhsh (1), Peter Mora (2), Hunter Bouillion (1), Ishita Pal (1), Manavi M Jadhav (1)

Affiliation: (1)University of Louisiana at Lafayette, Lafayette, LA, United States, (2) King Fahd University of Petroleum and Minerals

Abstract:

During planetary accretion, impacts vary in mass, velocity, and angle, producing magma oceans (MO) of different sizes, temperatures and silicate/metal ratio. The depth, composition and dynamics of the MO can affect elemental and isotopic partitioning, core differentiation, atmosphere formation, and so on of the newly formed planet. Of particular importance are large impactors, more common in the late accretionary stages, which create new magma, due to transformation of their kinetic into thermal energy, and contain iron cores that can emulsify into small drops, which then rain down into the rocky planetary core.

We show results of models of two phases of planetary building. (i) Evolution of the magma ocean volume over time, in conjunction with the buildup of an outgassed steam atmosphere. This is obtained by running 20 planetary accretion simulations over the span of 100 million years, using a modified version of Mercury 6.2. We aim at establishing whether magma oceans persist during the entire growth of a terrestrial planet, and predict their volume vs time. (ii) Preliminary models of iron rain, based on a newly developed fluid-dynamic numerical approach based on the Lattice Boltzmann Method. We focus on a realistic range of magma ocean scenarios and track the descent cloud of iron drops formed out of the impactor’s core, through an entire magma ocean, identifying the descent environment (velocity, P-T, path, entrainment amount).

References

1. Nikolaou, A. et al., (2019) ApJ 875(1), 11.

2.Hosono, N. et al., (2019) Nat. Geosci. 12, 418- 423.

3. Chambers, J. E. (1999) MNRAS, 304(4), 793-799.

4. Nakajima, M. et al., (2021) Earth Planet. Sci. Lett. 568, 116983.

5. Tucker, J. M., & Mukhopadhyay, S. (2014). Earth Planet. Sci. Lett. 393, 254-265.

6. P Mora, G Morra, DA Yuen (2020). Geophysical Journal International 220 (1), 682-702

Author(s): Steven Rendon Restrepo and Pierre Barge

Affiliation: Aix Marseille Univ, CNRS, CNES, LAM, France

Abstract:

Large scale vortices are thought to be natural outcomes of hydrodynamic instabilities in protoplanetary discs, as for instance the Rossby wave instability [1] or Baroclinic instability. Analytical and numerical studies showed that they can be long-lived and catalyze efficiently dust material concentration (e.g) [2], [3] and encourage to think they could play a role in protoplanetary disc evolution and planetesimal formation. Their presence in the outer regions of circumstellar discs is possibly betrayed by recent observations of lopsided structures with ALMA and VLT [4], [5] and raises also a question: what is the importance of disc self-gravity (SG) on their structure and evolution.

We present 2D hydrodynamical simulations of steady vortices evolving under the effect of their own gravity. The goal is to study their evolution and the possibility of gravitational collapse. Are particularly addressed the structure, migration, mass, and physical variables characterizing these self-gravitating structures. Based on Toomre’s criterion, we find a stability condition that vortices should satisfy to resist the destabilizing effects of SG and confirm that massive discs cannot host large-scale vortices. Finally, we show that high-resolution simulations are required to avoid artificial vortex decay [6].

References:

1. Lovelace, R. V. E., Li, H., Colgate, S. A., & Nelson, A. F. 1999, ApJ, 513, 805
2. Barge, P. & Sommeria, J. 1995, A&A, 295, L1
3. Tanga, P., Babiano, A., Dubrulle, B., & Provenzale, A. 1996, Icarus, 121, 158
4. Tsukagoshi, T., Muto, T., Nomura, H., et al. 2019, ApJ, 878, L8
5. Dong, R., Liu, S.-y., Eisner, J., et al. 2018, ApJ, 860, 124
6. Rendon Restrepo S. and Barge P. 2022, A&A, Accepted: 20 June 2022

Author(s): Carolina Schaefer (1), Giovanni Picogna (1), Barbara Ercolano (1), Raphael Franz (1), Christian Rab (1), and Matias Garate (2)

Affiliation: (1) Universitaets-Sternwarte, LMU, Muenchen, Germany, (2) Max-Planck-Institut für Astronomie, Heidelberg, Germany

Abstract:

Photoevaporative disc winds play a key role in our understanding of circumstellar disc evolution, especially in the final stages, and they might affect the planet formation process and the final location of planets. The study of transition discs is central for our understanding of the photoevaporation process. However, we need to distinguish cavities created by photoevaporation from those created by giant planets. Theoretical models are necessary to identify possible observational signatures of the two different processes, and models to find the differences between the two processes are still lacking. We study a sample of transition discs obtained from radiation-hydrodynamic simulations of internally photoevaporated discs, and focus on the dust dynamics relevant for current ALMA observations. We found a double peak emission close to the cavity specific to gaps carved by photoevaporation, which is however not observable with typical ALMA spatial resolutions. We then compared our results with models of gaps opened by super Earths/giant planets finding that the cavity steepness depends mildly with the gap size, and it is consistent with a 30 Earth mass planet. However, the dust density drops much more rapidly inside the cavity than in the planetary case due to the more efficient dust filtering. This effect is clearly visible in the spectral index, which shows a sharper increase at the cavity edge with respect to the planetary case. The combination of cavity steepness and spectral index might reveal the true nature of transition discs.

Author(s): Mark Booth (1), Tim D. Pearce (1), Alexander V. Krivov (1), Mark C. Wyatt (2), William R. F. Dent (3), Antonio S. Hales (3,4), Jean-François Lestrade (5), Fernando Cruz-Sáenz de Miera (6), Virginie C. Faramaz (7), Torsten Löhne (1) and Miguel Chavez-Dagostino (8)

Affiliation: 1 AIU, FSU, Jena, Germany (2) IoA, University of Cambridge, UK (3) Joint ALMA Observatory, Santiago, Chile (4) NRAO, Virginia, USA (5) Observatoire de Paris, France (6) Konkoly Observatory, Budapest, Hungary (7) Steward Observatory, University of Arizona, USA (8) INAOE, Mexico

Abstract:

Epsilon Eridani is the closest star to our Sun known to host a debris disc. Prior observations in the (sub-)millimetre regime have potentially detected clumpy structure in the disc and attributed this to interactions with an (as yet) undetected planet. However, the prior observations were unable to completely distinguish between structure in the disc and background confusion. Here we present the first ALMA image of the entire disc, which has a resolution of 1.6″ × 1.2″. We clearly detect the star, the main belt and two point sources. The resolution and sensitivity of this data allow us to clearly distinguish background galaxies (that show up as point sources) from the resolved,
clumpy emission in the disc. We show that the two point sources are consistent with background galaxies. After taking account of these, we find that resolved clumpy emission is still present in the main belt, including two clumps with a >3σ significance – one to the east of the star and the other to the northwest. We perform n-body simulations to demonstrate that a migrating planet can form structures similar to those observed by trapping planetesimals in resonances. We find that the observed features can be reproduced by a migrating planet trapping planetesimals in the 2:1 mean motion resonance and the symmetry of the most prominent clumps means that the planet should have a position angle of either ∼10° or ∼190°.

Author(s): Enrique Sanchis (1), Lena Noack (1), Gregor J. Golabek (2)

Affiliation: (1) Institute of Geological Sciences, Freie Universitaet Berlin, Berlin, Germany, (2) Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany

Abstract:

Magma oceans play a fundamental role in the thermal evolution of rocky planets and moons. Most of these objects experience a magma ocean phase at least at their very early ages, since temperatures are expected to be very high mainly due to radiogenic heating and the release of graviational energy. In addition, it is also possible to find, long after their formation, very hot planets or moons that contain large magma oceans in their interior. Perhaps the most famous example is Io. Due to strong tidal interactions with Jupiter and its moons, Io suffers from extreme tidal heating, strong enough to melt large regions of its interior.

Mantle convection simulations are crucial to understanding the long-term thermal evolution of rocky planets and moons. These simulations are tailored to solid convection in the mantle. Properties such as the viscosity and the thermal conductivity are several orders of magnitude different between solidus and liquidus. These large differences pose numerical restrictions that make the codes unstable and prone to crash. As consequence, simulating the interior thermal evolution of hot rocky planets and moons with mantle convection codes turns out to be extremely challenging.

In this work, we apply our magma oceans modeling to Io, since it is an appropriate test case in the Solar System with evidence of hosting large amounts of magma in its interior (e.g., Khurana et al. 2011). We use the CHIC convective code (Noack et al. 2015) to model Io’s interior thermal evolution. We then apply and expand an approach, originally developed by Golabek et al. 2011, in which the effective local properties are altered wherever melt is present or produced. Our modeling can be applied to any rocky planet with hot interiors, as could be the case of the innermost Trappist-1 planets, or many of the rocky exoplanets known.

References

Golabek, G. J., Keller, T., Gerya, T. V., et al. 2011, Icarus, 215, 346.
Khurana, K. K., Jia, X., Kivelson, M. G., et al. 2011, Science, 332, 1186.
Noack, L., Rivoldini, A., & Van Hoolst, T. 2015, in EGU General Assembly Conference Abstracts, EGU General Assembly Conference Abstracts, 14854.

Author(s): Kolja Joeris (1), Laurent Schönau (1), Matthias Keulen (1), Philip Born (2), Jonathan E. Kollmer (1)

Affiliation: (1) University of Duisburg-Essen, Germany, (2) DLR – Institute of Material Physics in Space, Germany

Abstract:

As apparent on the images taken of asteroid 25143 Itokawa by the space probe Hayabusa, its surface is covered by rocks of various sizes. Those rocks appear to be sorted by size, forming ponds of small particles clearly segregated from boulder-dominated formations [1]. One Hypothesis is that this segregation stems from the Ballistic Sorting Effect (BSE), as proposed by Shinbrot [2]. The BSE is caused by different rebound behaviors for impactors depending on the target particle size. An impactor hitting a bed of small particles will lose energy more efficiently than the same impactor on a target consisting of larger rocks. We designed an experiment to test this hypothesis by creating a realistic artificial asteroid environment with the aid of the ZARM drop tower in Bremen [3].

The experimental data show a more complex behavior of the coefficient of restitution (COR) with respect to target particle size than expected when only referring to the BSE. We find, and with the aid of numerical simulations confirm, a minimum in the COR for a specific target particle size [4]. Furthermore, we identify interparticle cohesion to be the reason of this minimum. To conclude our findings, we observe that in a cohesion dominated regime the ballistic sorting can be even more efficient for specific particle sizes than in mainly gravity dominated environments.

References

[1] A. Fujiwara,J. Kawaguchi,D.K. Yeomans,M. Abe, T. Mukai, T. Okada, J. Saito, H. Yano,M. Yoshikawa, D.J. Scheeres et al., Science312,1330 (2006)

[2] T. Shinbrot, T. Sabuwala, T. Siu, M.V. Lazo,P. Chakraborty, Phys. Rev. Lett. 118(2017)

[3] K. Joeris, L. Schönau, L. Schmidt, M. Keulen, V. De-sai, P. Born, J. E. Kollmer, EPJ Web of Conferences249, 13003 (2021)

[4] K. Joeris, L. Schönau, M. Keulen, P. Born, J. E. Kollmer, NPJ Mircogravity, 8 (2022)

Author(s): Vincent Böning (1), Wieland Dietrich (1), and Johannes Wicht (1)

Affiliation: (1) MPI for Solar System Research, Göttingen

Hot Jupiters orbit their host star in a very close orbit and in synchronous rotation. Recent results (see poster of Dietrich et al.) suggest that the combination of strong, irradiation-driven winds and the large electrical conductivity driven by thermal ionisation of metals will induce strong horizontal magnetic fields and likely allow an independent self-sustained dynamo in the stratosphere of (Ultra) Hot Jupiters. Our aim is to understand the influence of magnetic effects on radius inflation via Ohmic dissipation and on atmospheric flows via the Lorentz force.

Here we show preliminary results from a three-dimensional magneto-hydrodynamic model of a self-excited stratospheric dynamo with constant conductivity. The model equations govern the conservation of momentum, thermal energy, and the induction equation in a stratified spherical shell, which is perturbed by an irradiation term. The model parameters are chosen such that the magnetic Reynolds number matches estimates for Kelt-9b, which has an equilibirum temperature of about 4000 K. We characterize how the initial infinitesimal seed field is amplified by the strong shear of the atmospheric winds and by the weaker radial flows that are driven by the irradiation. We show a typical magnetic field configuration and analyze how the growth of the magnetic field saturates.

Author(s): Vincent Böning (1), Paula Wulff (1,2), Wieland Dietrich (1), Johannes Wicht (1), Ulrich Christensen (1)

Affiliation: (1) MPI for Solar System Research, Göttingen, (2) University of Göttingen

Abstract:

The precise mechanism that forms jets and large-scale vortices on the giant planets is unknown. An inverse cascade has been suggested by several studies to drive these phenomena. Alternatively, energy may be directly injected into the jets by small-scale convection. Since jets and large-scale vortices likely form in the presence of deep convection, our aim is to clarify whether an inverse cascade is operating in a system of rapidly-rotating deep spherical-shell convection. We analyze the non-linear scale-to-scale transfer of kinetic energy in such simulations as a function of the azimuthal wave number m. We find that the main driving of the jets is associated with upscale transfer directly from the small convective scales to the jets. This transfer is very non-local in spectral space, bypassing large-scale structures. The jet formation is thus not driven by an inverse cascade. Instead, it is due to a direct driving by Reynolds stresses, statistical correlations of velocity components of the small scale convective flows. Initial correlations are caused by the eect of uniform background rotation and shell geometry on the flows and provide a seed for the jets. While the jet growth suppresses convection, it increases the correlation of the convective flows, which
further amplifies the jet growth until balanced by viscous dissipation. To a much smaller extent, energy is transferred upscale to large-scale vortices directly from the convective scales, mostly outside the tangent cylinder. There, large-scale vortices are not driven by an inverse cascade either. Inside the tangent cylinder, the transfer to large-scale vortices is even weaker, but more local in spectral space, leaving open the possibility of an inverse casacade as a driver of large-scale vortices. In addition, large-scale vortices receive kinetic energy from the jets via forward transfer. We therefore suggest a jet instability as an alternative formation mechanism of large-scale vortices.

Author(s): Thomas Pfeil (1,2), Til Birnstiel (1), Hubert Klahr (2), Miles Cranmer (3), Shirley Ho (3)

Affiliation: (1) University Observatory, LMU, Munich, Germany (2) Max Planck Institute for Astronomy, Heidelberg, Germany (3) Center for Computational Astrophysics, Flatiron Institute, New York, USA

Abstract:

Planetesimal formation is believed to occur via Streaming Instability and/or gravoturbulent collapse of dust overdensities in protoplanetary disks. The origins of the physical conditions allowing these mechanisms to set in, e.g., high dust-to-gas ratios in combination with large particles size, are poorly understood.
Hydrodynamic simulations of protoplanetary disks with an evolving dust population are, thus, indispensable tools for studies of the early phases of planet formation. Simulations in more than one dimension are, however, prohibitively complex and computationally expensive when conducted with common numerical methods.
We present 2pop, a two-population dust coagulation model for hydrodynamic simulations with the PLUTO code. 2pop evolves a power law dust size distribution parametrized by only two dust fluids and a maximum particle size, instead of the usually needed ~100 mass bins.
Since the assumptions made in the derivation of 2pop lead to inaccurate results in some cases, like in planetary gaps or disks around very low mass stars, we are also applying machine learning techniques to create an additional neural network version of the 2pop, inferred from 10000 full dust coagulation simulations. We will further test this version in hydrodynamic simulations and use it to improve the „classical“ 2pop.

Author(s): Sandra V. Jeffers (1), J.R.Barnes (2), P.Schöfer (3), A.Quirrenbach (4), M.Zechmeister (3), P.J. Amado (5), J.A.Caballero (6), M. Fernandez (5), E. Rodriguez (5), I. Ribas (7,8), A. Reiners (3), C. Cardona Guillen (9,10), C. Cifuentes (6), S. Czesla (11), A.P. Hatzes (12), M.Kurster (13), D.Montes (14), J. C. Morales (7,8), S. Pedraz (15), S. Sadegi (4,12) and the CARMENES team

Affiliation: (1) Max Planck Institute for Solar System Research, Göttingen (2) Open University, Milton Keynes, UK, (3) Institut für Astrophysik Göttingen, (4) Landessternwarte Königstuhl, (5) Instituto de Astrofísica de Andalucía (IAA-CSIC), (6) Centro de Astrobiología Madrid, (7) Institut de Ciències de l’Espai, (8) Institut d’Estudis Espacials de Catalunya (IEEC), (9) IAC, Tenerife, (11) Hamburger Sternwarte, (12) Thuringer Landessternwarte, (13) Max-Planck Institute for Astronomy, Königstuhl, (14) Universidad Complutense de Madrid, (15) Calar Alto Observatory

Abstract:

Current exoplanet surveys using the RV technique are targeting M dwarfs because any habitable zone terrestrial-mass planets will induce a high RV and orbit on shorter periods than for more massive stars. One of the main caveats is that M dwarfs show a wide range of activity levels from inactive to very active, which can induce an asymmetry in the line profiles and, consequently, a spurious RV measurement. We investigate the impact of stellar activity on the visible and near-infrared Radial Velocity (RV) measurements of the active M 3.5 dwarf EV Lac using high-precision CARMENES spectra. We conclude that (1) care should be taken when interpreting periodicities in activity indicators in data taken over a long time span, and (2) a regular cadence (i.e. nightly) observing strategy is the most efficient way to identify and mitigate sources of stellar activity.

Author(s): Sandra Jeffers

Affiliation: Max-Planck Institute for Solar System Research

Abstract:

The detection of exoplanets around our nearest stellar neighbours, especially potentially Earth-like planets, is one of the most exciting and inspiring scientific quests of our time. The RedDots exoplanet search program aims to search for all of the terrestrial planets orbiting within a distance of 5pc using the Radial Velocity technique . Since we are completing a volume-limited sample we have the additional challenge of detecting exoplanets orbiting very magnetically active stars. Here, I will present our unique observing strategy, our latest results, especially how to mitigate stellar activity, and our future plans.

Author(s): Sascha Grziwa (1), Martin Pätzold (1)

Affiliation: (1) Rheinisches Institut für Umweltforschung, Abt. Planetenforschung, an der Universität zu Köln

Abstract:

Most confirmed planets known by date were detected in high resolution stellar light curves of the space missions CoRoT, Kepler, K2 and TESS. Most detection methods make use of the periodicity of the transit in the light curve using Box leased square (BLS) algorithm or frequency analysis (e.g. FFT, wavelet analysis). These algorithms usually need three transits at least for a detection (light curves more than two times the length of the orbital period of the transit). Planets with only one transit visible in the light curve (single transits, mono transits) are usually not detected with these automatic pipelines. Single transits of binaries or large planets (Jupiter planets) are partially found by visual search or analysis of detections in multi-planet systems. Most of the planetary single transits of shallow depth (Neptune, Super-Earth planets) are still hidden in the archive data. Especially the relatively short light curves of K2 and TESS shall include many single transits of planets up to a period of 100 days not found yet.

In this SPP1992 project we develop a single transit detection pipeline using our existing wavelet based transient search algorithm SINGLETRANS. The available archive data of CoRoT, Kepler, K2 and TESS shall be searched for unknown single transits of especially small radius planets. Our pipeline will help to populate the area of planetary candidates with larger orbital periods. Detected single transits can be confirmed by ground-based follow-up (RV-measurements) or additional transit observation (e.g. CHEOPS). The additional number of detected candidates with larger orbital periods shall help to increase the diversity of exoplanets. In the future early detections of single transits in light curves of the upcoming PLATO mission can help to priorities transit candidates and forecast the following transits. Our first tests show that SINGLETRANS is suitable to detect also periodic and ‘quasi periodic’ (strong TTV, circumbinary planets) transits.

Author(s): Miriam Fritscher (1) and Jens Teiser (1)

Affiliation: (1) University of Duisburg-Essen

Abstract:

The coagulation of micrometer-sized solid particles is the first step in planetesimal formation. In the inner parts of a protoplanetary disk, silicate dust is the predominant material. In the outer parts beyond the corresponding snowlines, volatile compounds such as H₂O or CO₂ condense and serve as additional building material. To understand the first steps in planetesimal formation, it is essential to investigate the collisional and the mechanical properties of the materials involved. The experiments presented here contribute to a broader understanding of these properties of CO₂.

Collisions are studied with agglomerate sizes of 10 µm to 150 µm at a temperature of around 100 K and a pressure of 1 mbar. The impact velocities reach up to 3.4 m/s. The collisional outcome is analyzed regarding the events of sticking, bouncing and fragmentation [1].

The mechanical properties are examined using the Brazilian test. The splitting tensile strength is determined for varying volume filling factors. The effective surface energy of CO₂ ice is derived from the measured splitting tensile strength [2].

The experiments indicate that CO₂ ice behaves similarly to silicate dust regarding the collision properties. It can be assumed that the growth processes including the growth barriers known for silicates also apply to CO₂ ice.

References

[1] Fritscher, M. and Teiser, J. (2021) ApJ, 923, 134. DOI: 10.3847/1538-4357/ac2df4

[2] Fritscher, M. and Teiser, J. (2022) MNRAS, 512, 3754-3759. DOI: 10.1093/mnras/stac676

Author(s): Anna Julia Poser (1), Nadine Nettelmann (2), Ronald Redmer (1)

Affiliation: (1) Institut für Physik, Universität Rostock, Rostock (GER) (2) Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt, Berlin (GER)

Abstract:

Giant planets may inhibit valuable information in their interiors and atmospheres [1]. Their current internal structure and today’s observed luminosity is especially determined by their long-term internal evolution due to contraction and cooling. For cooler gas giants (Teq<1000K), evolutionary calculations can predict today’s measured luminosity and radius. But for warmer planets (Teq>1000K), additionally extra energy mechanisms are needed to explain the measured radius [2,3]. Slowing down contraction due to higher atmospheric opacities and a consequently reduced cooling rate has been discussed previously as a possible contributing mechanism to the observed radius inflation, e.g., [4]. Further, Müller et al. (2020) showed that a heavy-element enhanced opacity may inflate low-metallicity planets [5]. An enhanced opacity in the atmosphere can be due to a higher metallicity or due to clouds and hazes as expected to be found in almost all giant planets.

Of particular interest to us is in what way an opacity enhanced atmosphere due to additional absorbers such as clouds influence the planetary thermal evolution, particularly the radius evolution. Therefore we couple the thermal evolution, interior structure models and atmospheric models, similar to Poser et al. (2019) [6]. To approximate the long-term atmospheric evolution, we simulate cloud decks in an ad-hoc manner via the semi-analytical model by Heng et al [7,8]. In detail, the cloud deck location and the cloud opacity are tagged along the thermal evolution. This allows us to study at first order how time-varying cloud decks may influence the radius evolution of giant planets. We look into the effects of different cloud deck locations and opacities on the radius for young and evolved planets, such as TOI-1268b, WASP-39b and WASP-103b and KELT-9b.

References

1. Helled, R. et al. (2022) Exp. Astron. 53, 323–356
2. Thorngren, D. P. et al. (2018) AJ 155, 214
3. Sarkis, P. et al. (2021) A&A 645, A79
4. Burrows, A. et al. (2007) ApJ, 661, 502
5. Müller, S. et al. (2020) ApJ 903 147
6. Poser, A. J. et al. (2019) Atmosphere 10(11), 664
7. Heng, K. et al. (2012) MNRAS 420, Issue 1, 20–36
8. Guillot, T. (2010) A&A 520, A27

Author(s): Tim Becker, Tobias Steinpilz, Jens Teiser, Gerhard Wurm

Affiliation: University of Duisburg-Essen, Germany

Abstract:

In recent years, collisional charging has been proposed to promote the growth of pebbles in early phases of planet formation. Ambient pressure in protoplanetary disks spans a wide range from below $10^{-9}$ mbar up to way beyond mbar. Yet, experiments on collisional charging of same material surfaces have only been conducted down to $10^{-2}$ mbar thus far. We present first pressure dependent charge measurements of same material collisions between $10^{-8}$ and $10^3$ mbar as well as some insight on typical discharge times of charged surfaces under different conditions. We show that not only strong charging occurs down to the lowest pressure, but the charges also remain on the surface long enough to be relevant for the next collision event. In detail, our observations show a strong similarity to the pressure dependence of the breakdown voltage between two electrodes and we suggest that breakdown also determines the maximum charge on colliding grains in protoplanetary disks. We conclude that collisional charging can occur in all parts of protoplanetary disks relevant for planet formation.

Author(s): Jan-Vincent Harre and the CHEOPS consortium

Affiliation: Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany

Abstract:

Orbital decay is suspected to occur especially for hot Jupiters, with the only observationally confirmed case of this being WASP-12b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q′∗, which describes the efficiency with which kinetic energy of the planet is dissipated within the star. Using newly acquired photometric CHEOPS and TESS observations, and by re-analyzing archival data, we aim to improve current orbital decay fits and parameters for the KELT-16 and WASP-4 systems, and for the first time give an estimate for the KELT-9 system. Furthermore, we want to solve the TTVs of HD 97658 b, which prior to this work have been indicative of an increasing orbital period. Making use of the fit results obtained by fitting a stable orbit, an orbital decay, and an apsidal precession model to the transit and occultation timings, which were acquired using state-of-the-art MCMC algorithms, we compare the BIC values of the three models for each system to infer the model describing each system the best, while also accounting for the number of parameters in each fit. Additionally, for our orbital decay targets KELT-9 b, KELT-16 b, and WASP-4 b, we calculate their respective Q′∗ values based on the best-fit orbital decay parameters. We find that all examined systems are best described by a constant orbital period model, according to the resulting BIC values. However, in the case of WASP-4 b, the orbital decay model shows a significant trend (> 5σ), with the new CHEOPS data also possibly indicating a non-linear ephemeris. Likewise, in the case of the KELT-9 system, the recently obtained TESS and CHEOPS transit observations could hint towards a quadratic ephemeris, but more observations in the future are necessary to conclude these presumptions. For HD 97658 b, we solve the TTV issue and confirm a linear ephemeris, ruling out the previously suspected quadratic trend.

Author(s): Susanne Pfalzner (1), Michele Bannister (2)

Affiliation: (1) Forschungszentrum Jülich, Germany

Abstract:

The discovery of the two interstellar objects, 1I/‘Oumuamua and Borisov, confirmed that planetesimals must exist in significant numbers in interstellar space. Originally generated during planet formation, Interstellar objects (ISOs) are scattered from their parent systems and drift through interstellar space. Observational constraints infer a density of 10¹⁵ ISOs per cubic parsec. Here we address the question of whether ISOs can follow the collapse of molecular clouds, into discs and possibly influence planet formation. We perform low-resolution simulations of the collapse of molecular clouds containing initially static ISO populations toward the point where stars form. We find that the ISOs definitely follow the collapse of the gas, and many become bound to the stars. As a consequence they should seed molecular clouds with at least hundred-meter-scale objects. We consider how the galactic background density of planetesimals, enriched from successive generations of star and system formation, can be incorporated into forming stellar systems. We find that at a minimum of the order of 10⁷ ‘Oumuamua-sized and larger objects, plausibly including hundred-kilometer-scale objects, should be present in protoplanetary disks. At such initial sizes, the growth process of these seed planetesimals in the initial gas- and dust-rich protoplanetary disks is likely to be substantially accelerated. This could resolve the tension between accretionary timescales and the observed youth of fully fledged planetary systems. Our results strongly advocate that the population of interstellar planetesimals should be taken into account in future studies of planet formation. As the density of interstellar objects increases over time, we hypothesize that this enriched seeding accelerates and enhances planetary formation after the first couple of generations of planetary systems.

Author(s): Kevin Ollmann

Affiliation: Institut für Theoretische Physik und Astrophysik (Christian-Albrechts-Universität zu Kiel), Deutschland

Abstract:

We evaluate the impact of hot exozodiacal dust on the analysis of polarized scattered light of close-in exoplanets. This study is particulary motivated by the recently proven feasibility of exoplanet polarimetry (Bott et al. 2018, Bailey et al. 2021).

Hot exozodiacal dust is located very close to the star, potentially at similar orbital radii as close-in planets. Current models explain their infrared excess by an optically thin, narrow dust ring located close to the dust sublimation radius. We analyze to what extent the existence of hot exozodiacal dust might influence the polarimetric characterization of hot Jupiter planets and vice-versa. Besides the individual properties of the planetary atmosphere and the dust particles, the effect of gravitational interaction between the planet and the dust is considered.

Author(s): H. L. Ruh (1), P. Capone (2), S. Dreizler (1), T. Henning (3), A. Quirrenbach (2), A. Reiners (1), M. Zechmeister (1)

Affiliation: (1) Institut für Astrophysik und Geophysik, Georg-August-Universität, Germany, (2) Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Germany, (3) Max-Planck-Institut für Astronomie, Germany

Abstract:

Ultra-cool M dwarfs present unique challenges and opportunities to the radial velocity (RV) exoplanet-hunting community: Albeit those stars are intrinsically faint and overwhelmingly active, a dense forest of stellar lines in the near-infrared exists to be exploited for the search of low-mass rocky
planets. Potentially, a large number of low-mass planets can be detected due to the large frequency of low-mass planets around M dwarfs, which are the most common stars in the solar neighborhood.
We monitor Doppler shifts in the spectra of ten M5 to M8-type stars (J = 9.8 to 12.2 mag) with the Habitable-zone Planet Finder (HPF). In our first year of observations, we obtained 57 spectra and reach a median RV precision of 19.7 m/s. This survey will allow us to discover 10 M⊕ planets in the habitable zones of their host-stars and investigate the effects of stellar activity in ultra-cool M dwarfs.

Author(s): Jakob Penner (1), Jens Teiser (1), Gerhard Wurm (1)

Affiliation: (1) Faculty of Physics, University of Duisburg-Essen, Germany

Abstract:

In planet formation models there is a size gap between growth by coagulation of solids and gravitational growth. One potential way to cross this size gap is a model based on the effect of oppositely charged particles and their attractive forces. Experiments showed that tribocharging during collisions is very efficient. Recent experiments showed that charge conservation is violated during the collisions of charged particles. One possible explanation for this could be charge transfer into the surrounding gas, thus ionizing it. To verify this hypothesis we try to measure the ionization of air with a cylindric capacitor that has a design inspired by a Gerdien tube. This capacitor is built into a series connection together with a DC source and a resistor with high impedance. We induce continuous collisions  of an ensemble of particles using a shaking mechanism. Ions that are generated by these tribocharging events, will induce a current if they collide with one of the electrodes of the cylindrical capacitor. This will lead to a current resulting in a voltage at the high impedance resistor. Hence the ions will ultimately be detected by measuring the change of voltage at the high impedance resistor. With my poster I will give an overview of the work in progress, including the details of the experimental setup and preliminary results.  

Author(s): Aymeric Fleury (1), Ana-Catalina Plesa (1), Nicola Tosi (1), Doris Breuer (1)

Affiliation: (1) Department of Planetary Physics, German Aerospace Center (DLR), Berlin, Germany

Abstract:

Mercury experiences significant surface temperature variations between its polar region and its equatorial region due to its very low obliquity, a pattern that is thought to play a central role on the planet’s interior evolution and thermal state. In addition, lateral variations of the crustal thickness based on the MESSENGER gravity and topography data [1] can also affect the temperature distribution of the lithosphere and mantle as it was suggested for Mars [2]. In this study, we investigate the effects of surface temperature and crustal thickness variations on the thermal evolution of the interior of Mercury, and compare our results to local elastic thickness estimates (e.g. [3]).

We combine the geodynamical code GAIA [4] with the surface temperature variations and crustal thickness data similar to [2]. All simulations are done in a full 3D spherical geometry, use the extended Boussinesq Approximation, and consider core cooling and radioactive decay. The pressure- and temperature-dependent viscosity [5] follows an Arrhenius law of diffusion creep.

We use a pressure- and temperature-dependent thermal expansivity and conductivity in the mantle, as well as a crust, which is enriched in heat producing elements (HPEs). We test several crustal thickness models of [1], namely model U0, V0, V3 and V4. Additionally, our models include surface temperature variations.

Our models indicate that the surface temperature variations of Mercury introduce a long-wavelength pattern on the heat flux and mechanical thickness. The crustal thickness variations and enrichment of the crust in HPE, on the other hand, lead to smaller scale perturbations that may affect the local heat flux and mechanical thickness values. We calculate local values of the mechanical lithosphere thickness during the early evolution of Mercury in order to compare them with literature estimates of the elastic thickness to determine which models are compatible with observations.

References

1. Beuthe et al. (2020). Geophysical Research Letters, 47(9).

2.Plesa et al. (2018). Geophysical Research Letters, 45(22).

3.Goossens et al. (2022) The Planetary Science Journal, 3(145).

4.Hüttig et al.(2013). Physics of the Earth and Planetary Interiors, 220(11–18).

5.Tosi et al. (2013) Physics of the Earth and Planetary Interiors 217(48–58).

Author(s): Michaela Walterová (1), Marie Běhounková (2), Michael Efroimsky (3)

Affiliation: (1) DLR Institute of Planetary Research, Berlin, Germany, (2) Department of Geophysics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic, (3) US Naval Observatory, Washington DC, USA

Abstract:

Interpretation of the data obtained throughout the period of more than 40 years by Lunar Laser Ranging yields an interesting observation: the tidal quality factor of the Moon, which determines the magnitude of ongoing energy dissipation, follows a different frequency dependence than is measured for rocks in laboratory conditions (e.g., [1]). When the self-gravity of the lunar body is taken into account, the detected frequency dependence can be interpreted as a signal coming from strong dissipation at the lunar base [2], indicating a deep-seated layer with low viscosity and possibly containing partial melt (e.g., [1,3,4]). Such a layer would be consistent with the non-detection of farside moonquakes by nearside seismic stations [5] and is often associated with the ilmenite-bearing cumulates, that are thought to have descended onto the core-mantle boundary during the lunar magma ocean solidification. Alternative models of a melt-free lunar mantle have also been proposed (e.g., [6]). These models fit the tidal quality factor Q at the monthly frequency but were unable to explain its observed frequency dependence.

In this study, we propose a melt-free model, in which the frequency dependence of lunar Q emerges due to elastically accommodated grain-boundary sliding (GBS) in the lunar mantle (e.g., [7]). We discuss the implications of such a model and compare it with the traditional approach, which assumes a highly dissipative basal layer. For both alternatives, we perform a Bayesian inversion of the measured tidal parameters (tidal quality factor Q at the monthly and the annual frequency, degree-2 Love numbers h₂, k₂, and degree-3 Love number k₃) and predict either the conditions at the base of the lunar mantle or the relaxation time of elastically accommodated GBS. Since the two alternative models prove to be indistinguishable from each other by tidal measurements, we conclude with an outlook on future observations.

References

[1] Williams, J. G. et al. (2001), J. Geophys. Res., 106(E11):27933–27968.

[2] Harada, Y. et al. (2014), Nat. Geosci., 7(8):569–572.

[3] Efroimsky, M. (2012), Celest. Mech. Dyn. Astron., 112(3):283–330.

[4] Khan, A. et al. (2014), J. Geophys. Res. Planets, 119(10):2197–2221.

[5] Nakamura, Y. et al. (1973), Science, 181(4094):49–51.

[6] Nimmo, F. et al. (2012), J. Geophys. Res. Planets, 117(E9).

[7] Sundberg, M. and Cooper, R. F. (2010), Philos. Mag., 90(20):2817–2840.

Author(s): Tommy Chi Ho Lau Author (1), Joanna Drążkowska Co-Author (1,2), Sebastian M. Stammler Co-Author (1), Tilman Birnstiel Co-Author (1,3), Cornelis P. Dullemond Co-Author (4)

Affiliation: (1) LMU, Germany, (2) Max Planck Institute for Solar System Research, Germany, (3) Exzellenzcluster ORIGINS, Germany, (4) Heidelberg University, Germany

Abstract:

Models of planetary core growth by either planetesimal or pebble accretion are traditionally disconnected from the models of dust evolution and formation of the first gravitationally-bound planetesimals. The state-of-the-art models typically start with massive planetary cores already present. We aim to study the formation and growth of planetary cores in a pressure bump, motivated by the annular structures observed in protoplanetary disks, starting with sub-micron-sized dust grains. We connect the models of dust coagulation and drift, planetesimal formation in the streaming instability, gravitational interactions between planetesimals, pebble accretion, and planet migration, into one uniform framework. We find that planetesimals forming early at the massive end of the size distribution grow quickly dominantly by pebble accretion. These few massive bodies grow on the timescales of ~100 000 years and stir the planetesimals formed later preventing the emergence of further planetary cores. Additionally, a migration trap occurs allowing for retention of the growing cores. Pressure bumps are favourable locations for the emergence and rapid growth of planetary cores by pebble accretion as the dust density and grain size are increased and the pebble accretion onset mass is reduced compared to a smooth-disk model.

Author(s): Julia M. Schmidt and Lena Noack

Affiliation: Freie Universität Berlin, Germany

Abstract:

The thermal evolution and atmosphere development of terrestrial (exo-)planets depends on a number of processes in the interior. For instance, inside the planetary rocky mantle, heat producing elements like potassium, thorium, and uranium influence the long-term thermal evolution of a planet. Due to melting processes inside the planet, these elements are redistributed towards the planet’s surface. This redistribution causes a shift in the heat budget between a planet’s crust and mantle, which in turn has an influence on the melt production and growth rate of the crust. The same is true for volatiles that are initially stored in the mantle, but unlike the heat producing elements, these elements are outgassed and contribute to the atmospheric layer on top of the crust.

In this study, we developed a 1D interior evolution code for terrestrial planets which models amongst others the thermal evolution of a planet, thickness of crust and lithosphere, outgassing of H₂O and CO₂, and the overall concentration of the redistributed heat producing elements for several planets and moons inside our solar system. We compare models including depth- and temperature-dependent redistribution processes to models with constant redistribution factors and how they affect the heat producing elements. Additionally, we vary other starting parameters and again compare how this affects the amount of the elements that were redistributed into the crust or outgassed into the atmosphere. We run the model for different planet sizes and starting temperatures. By constraining the effects of depth-dependent redistribution and variable starting parameters, the study can help us understanding for which types of terrestrial planets the more complex approach is relevant.

Author(s): Irene Bernt (1), Ana-Catalina Plesa (1), Sabrina Schwinger (1), Max Collinet (1) und Doris Breuer (1)

Affiliation: (1) German Aerospace Center (DLR), Institute for Planetary Research, Germany

Abstract:

Due to the Moon-forming impact the Moon was initially covered by a global magma ocean. Cooling and subsequent fractional solidification led to an initially layered lunar mantle composition. The aim of our work is to investigate how this mantle composition affects the convection and the subsequent melting of the lunar mantle.

In our work we use the mantle convection code GAIA [1] to model the thermochemical evolution of the Moon. We consider a compositionally heterogeneous mantle and, for comparison, a homogeneous lunar mantle scenario. For both scenarios, a petrological model [2] provides the initial density, melting curves, density change due to depletion, and, in case of a heterogeneous lunar mantle, the initial temperature profile and the initial layered structure. Our models use a 2D half cylinder geometry. We employ an Arrhenius law to calculate the temperature and depth dependent viscosity, and we account for core cooling, radioactive decay, and mechanical mixing. The mantle composition is tracked via a particle-in-cell method [3], where tracer particles carry information about material properties (density, melting temperature, degree of depletion, amount of heat producing elements). We account for latent heat consumption during melting and consider both the increase of solidus and the changes in density of the residual material due to mantle depletion.
We calculate the thickness of the secondary crust produced during the evolution and require that successful models fit present-day estimates of 0.4 – 12.4 km. This range accounts for both the basaltic lava flows (<1% of today’s crust [4]) and the Mg-suite rocks (6% to 30 %).

Our results show that a model with a homogeneous initial mantle composition either produces too much crust to match today’s estimates, or produces melt too late to match the ages of the oldest basalts. The heterogeneous models match the secondary crust estimates, but stop producing melt too early to account for the youngest lunar basalts.

Acknowledgements:
Irene Bernt and Sabrina Schwinger were supported by the German Research Foundation (Deutsche Forschungsgemeinschaft) SFB-TRR170, (subprojects C4 and A5).

References

[1] Hüttig C. et al. (2013) PEPI

[2] Schwinger S. and Breuer D. (2021) PEPI

[3] Plesa A.C. et al. (2013) IGI Global

[4] Head J.W. (1976) Rev. Geophys.

Author(s): Laetitia Allibert (1), Maylis Landeau (2), Nicole Güldemeister (1), Randolph Röhlen (1), Augustin Maller (2), Miki Nakajima (3), Victor Lherm (3), Lukas Manske (1), Kai Wünnemann (1)

Affiliation: (1) Museum für Naturkunde Berlin, Leibniz Institut for Evolution and Biodiversity Science, Berlin, Germany. (2) Institut de Physique du Globe de Paris, Université Paris Cité, Paris, France. (3) University of Rochester, Department of Earth and Environmental Sciences, Rochester, NY, United States

Abstract:

The relative amounts of highly siderophile elements in the Earth mantle are at odds with their predicted (at low P-T) partitioning between core and mantle. This has been suggested to result from different degree of partitioning at higher pressure/temperature or due to a late veneer. The efficiency of the latter depends on metal-silicate reequilibration during impacts. Models of planet formation indicate that Earth experienced multiple high-energy impacts, which are thought to have melted a large fraction of its silicate mantle. The depth of the produced magma ocean as well as the dispersion/fragmentation of the impactor’s core are important parameters to quantify the chemical reequilibration between metal and silicates and hence the composition of Earth’s core and Earth’s mantle. Both the melt production and the dispersion of the impactor’s material are explored here. (i) To quantify the melt production, iSALE3D has been used, coupled to the peak-shock pressure method further developed and adapted to iSALE as described by 1. to determine the melt production A large range of parameters (velocity, angle, initial thermal profile) is explored and the associated magma ocean depth is given. (ii) The mixing between metal and silicates is not yet quantified, however, a first approach, based on comparing numerical modelling and experiments is presented. Numerical simulations reproduce the shock physics of supersonic planetary impacts, but their spatial resolution is too limited to produce the turbulent features expected in a magma ocean, contrary to liquid impact experiments which are subsonic and hence neglect compressibility effects but show small-scale mixing and turbulence. We present a comparison of the cratering process in experiments and simulations at a similar impact velocity. We then progressively increase the velocity in impact simulations to reach supersonic conditions. and show that we can fit the regime transition between subsonic to hypersonic impacts.

Acknowledgments:
We gratefully thank the iSALE developers, including Gareth Collins, Kai Wünnemann, Dirk Elbeshausen, Boris Ivanov and Jay Melosh and Thomas Davison for the development of the pysaleplot tool. We also thank the Deutsche Forschungsgemeinschaft (SFB-TRR 170, subproject C2 and C4) for funding

References:
1. Manske, L., Marchi, S., Plesa, A.-C., & Wünnemann, K. (2021). Icarus, 357 , 114128.

Author(s): Frank Sohl (1), Jana Börner (2), Stefanie Garbade (3), Sarah S. Keßler (2), Detlev Konigorski (3), Ingo Retat (3), Volker Schmid (4), Lorenzo Schmitt (2), Carolin Schneider (2) and Klaus Spitzer (2)

Affiliation: (1) German Aerospace Center (DLR), Institute of Planetary Research, Berlin, Germany, (2) Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg, Germany, (3) Airbus Defense & Space GmbH, Bremen, Germany, (4) German Space Agency at DLR AR-AF BO – Forschung und Exploration, Bonn-Oberkassel, Germany

Abstract:

The MagVector/MFX-2 experiment was conducted in 2018 as part of Alexander Gerst’s horizons mission on the International Space Station (ISS). Its main objective was to enlarge the number of sensors for measuring effects of the Magvector/MFX core. Furthermore, the new sensor array gave an excellent opportunity to host 13 different material and planetary rock samples, for the first time measuring possible interactions with magnetic fields when travelling with orbital velocity in a laboratory experimental setup onboard the ISS. The magnetic environment around the samples was continuously monitored by 32 sensors measuring the magnetic flux density in three components. The meteorite samples and sample preparation were provided by the Museum für Naturkunde Berlin. The collected data material has been investigated using simulation and inversion software developed at the TU Freiberg. Here, we are going to report about the results of these virtual experiments that aim at reconstructing and understanding the observed magnetostatic and inductive responses generated by the samples. The known magnetic susceptibility of the samples was successfully recovered by a newly developed magnetostatic inversion algorithm after preprocessing the data to remove unphysical signal components. Furthermore, we have carried out a series of induction experiments using our Nedelec finite element unstructured tetrahedral mesh time-domain forward modeling code. Both codes allow for a highly accurate incorporation of the experimental geometry and the shape of the samples. The induction experiments showed that a significant inductive effect of the samples at the nearest sensor location cannot be expected below 1 to 10 kHz. Based on these findings, the method can be scaled up for the investigation of larger objects such as metal-rich asteroids.

Acknowledgments:
The Magvector/MFX experiment was planned and led by the German Space Agency at DLR and developed and built by Airbus Defense and Space GmbH with funds from the Federal Ministry for Economic Affairs and Energy (BMWi, now BMWK).

Author(s): Andreas Bartenschlager (1), Miriam Sinnhuber (1), Konstantin Herbst (2), John Lee Grenfell (3) and Fabian Wunderlich (3)

Affiliation: (1) Institut für Meteorologie und Klimaforschung, KIT, Germany, (2) Institut für Experimentelle und Angewandte Physik – Extraterrestrische Physik, CAU Kiel, Germany, (3) Institut für Planetenforschung – Extrasolare Planeten und Atmosphären, DLR, Germany

Abstract:

The launch of the James Webb Space Telescope (JWST) in December 2021 will open up the possibility of studying the composition of exoplanetary atmospheres in habitable zones, such as TRAPPIST-1e in the near future. With the help of numerical models of the exoplanetary atmospheres, the observations and the processes behind them can be better understood and interpreted (Herbst et al., 2022). We investigate the influence of stellar energetic particles (SEP) and galactic cosmic rays (GCR) on the atmospheres of exoplanets around an M-star. Here we use the ion chemistry model ExoTIC to investigate the influence of SEP and GCR events. In collaboration with the University of Kiel and DLR Berlin within the INCREASE project, we perform model experiments with different N2 dominated atmospheres and 0.1/1.0 bar CO2 partial pressure as well as humid and dry conditions (e.g. Wunderlich et al., 2020), taking into account the ionization rates for such events. Preliminary results show a significant impact of SEP events on the chemical composition of the atmosphere, including biosignatures such as O3. Since the events are of short duration, the atmosphere recovers quite quickly.

Acknowledgments:
We acknowledge the financial support of the German Research Foundation (DFG) via the project „The Influence of Strong Stellar Particle Events and Galactic
Cosmic Rays on Exoplanetary Atmospheres (INCREASE) (Project number 446096851)“.

References:

1. Herbst, K. et al. (2022) Astronomische Nachrichten, 343(4)
2. Wunderlich, F. et al. (2020) The Astrophysical Journal, 901(2)

Author(s): Alexander Bensberg (1) and Sebastian Wolf (1)

Affiliation: (1) Institute of Theoretical Physics and Astrophysics, University of Kiel, Germany

Abstract:

We present an algorithm for 3D time-dependent Monte Carlo radiative transfer. It allows the simulation of temperature distributions of dust configurations as well as corresponding images and spectral energy distributions of the scattered light and thermal reemission radiation in the case of embedded temporally variable radiation sources.

The algorithm is implemented in the publicly available 3D Monte Carlo radiative transfer code POLARIS (Reissl et al. 2016). The influence of the chosen temporal step width and the number of photon packages per time step is illustrated by simulations of the temperature distribution of a spherical dusty envelope around an embedded central star. The impact of the optical depth on the temperature simulation is discussed for the case of a spherical envelope as well as for a circumstellar disk. Finally, we present simulation results for the case of an outbursting star surrounded by a circumstellar disk.

Author(s): Luca Delussu Author (1), Til Birnstiel Co-Author (1), Anna Miotello Co-Author (2), Paola Pinilla Co-Author (3)(4) and Giovanni Rosotti Co-Author (5)(6)

Affiliation: (1) University Observatory, LMU Munich, Germany, (2) European Southern Observatory, Germany, (3) Max-Planck-Institut für Astronomie, Germany, (4) Mullard Space Science Laboratory, University College London, UK, (5) Leiden Observatory, Leiden University, Netherlands, (6) School of Physics and Astronomy, University of Leicester, UK

Abstract:

The advent of the Atacama Large Millimeter/Sub-Millimeter Array (ALMA) has marked a fundamental turning point in the field of protoplanetary disks. Large sample surveys of entire star-forming regions have uncovered remarkable correlations between several disk-star observables. In this context, the importance of disk population studies emerges as they make it possible to investigate such correlations.

We carried out a disk population study which simulated the evolution of dust and gas over millions of years of the protoplanetary disk’s life to constrain the initial conditions needed to reproduce the correlations and distributions observed. We exploited the twopoppy evolution code, which captures the viscous evolution of gas and dust surface density and particle size with high accuracy and short simulation times, thus providing a perfect tool for disk population studies. In particular, we focused on the distributions observed for disks‘ spectral index in the Lupus, Taurus and Ophiuchus regions.

Our simulations have shown the importance and necessity of the presence of substructures to reproduce the observed spectral indexes. Moreover, we outlined the characteristics of the required substructures and constrained the disks‘ initial conditions.

Author(s): Jonas Schwaak (1), Jens Teiser (1), Lothar Brendel (1), Dietrich Wolf (1) and Gerhard Wurm (1)

Affiliation: (1) University Duisburg-Essen, Germany

Abstract:

The stability of porous agglomerates is crucial for the evolution of solids in protoplanetary disks. Internal forces within an agglomerate are not only governed by surface forces (such as van der Waals interaction), but also long range forces resulting from electrically charged particles (such as Coulomb interaction or dipole forces) play an important role.

We present an ongoing experimental work to determine the binding forces of an aggregate consisting of multiple spherical particles with diameters between 425 µm and 450 µm. In the experiments, aggregates of multiple particles are injected into an acoustic trap and set in rotation.

A main focus of the investigations is the influence of charges generated by contact electrification on the binding forces.

The results, obtained so far, show that the chosen method, analyzing the trajectories, detachments and accelerations, can be successfully used in the acoustic trap to determine a lower limit for the stability of aggregates. Furthermore, first results indicate that it is feasible to study the acting forces during the detachment process.

Author(s): Eike W. Guenther

Affiliation: Thüringer Landessterwarte Tautenburg, Sternwarte 5, 07778 Tautenburg

Abstract:

Flares are known to play an important role for the evolution of the atmospheres of young planets. In order to understand the evolution of planets, it is thus important to study the flare-activity of young stars.  This is particularly the case for young M-stars, because they are very active.  We study photometrically and spectroscopically the highly active M-star 2MASS J16111534-1757214. We show that it is a member of the Upper Sco OB association, which has an age of 5-10 Myrs. We also re-evaluate the status of other bona-fide M-stars in this region and identify 42 members. Analysing the K2-light curves, we find that 2MASSJ16111534-1757214 has, on average, one super-flare withE> 1E35 erg every 620 hours, and one with E>E3 ,erg every 52 hours. Although this is the most active M-star in the Upper Sco association, the power-law index of its flare-distribution is similar to that of other M-stars in this region. 2MASSJ16111534-1757214 as well as other M-stars in this region show a broken power-law distribution in the flare-frequency diagram.  Flares larger than E>3E3 erg have a power-law index beta=-1.3+/-0.1 and flares smaller than that beta=-0.8+/-0.1. We furthermore conclude that the flare-energy distribution for young M-stars is not that different from solar-like stars.

References

Guenther E.W., Wöckel D., Chaturvedi P., Kumar V., Srivastava M.K., Muheki P. (2021,) MNRAS, 507, 2103.

Guenther E.W., 2022, MNRAS, 511, 1115.

Author(s): Florence Chioma Onyeagusi (1), Jens Teiser (1), Gerhard Wurm (1)

Affiliation: (1) University of Duisburg-Essen, Faculty of Physics, Lotharstr. 1, 47057 Duisburg, Germany

Abstract:

During inter-particle collisions in dust clouds, electric charge is transmitted via tribocharging, creating charge patterns on the individual grains and generating strong local electric fields. This greatly impacts further particle evolution and especially promotes a new phase of aggregation.

We conduct laboratory and microgravity experiments to investigate the charging behavior of sub-mm particles and the subsequent growth to larger agglomerates. In preparation for a sounding rocket flight, we already tested an experiment module during multiple shorter duration launches at the drop tower in Bremen. The sample material consists of sub-mm basalt and glass spheres. Here, we present our latest results concerning the growth and stability of colliding particle clusters.

Author(s): Oliver Henke-Seemann (1) and Lena Noack (1)

Affiliation: (1) Free University Berlin

Abstract:

Convective mantle flow of terrestrial planets is governed by a temperature- and pressure-dependent rheology. This results in a stagnant-lid regime observed on most terrestrial planets. Plastic deformation can lead to breaking of the strong upper lithosphere, which resembles plate tectonics on Earth.

Most efforts to model mantle convection with self-consistent plate tectonics combine Newtonian power-law with a stress-dependent pseudo-plastic rheology.
In the uppermost mantle, where stresses are high, deformation is thought to be driven partly by dislocation creep. This is often neglected in viscoplastic consideration, which employ purely diffusion-creep-driven flow combined with a yield criterion.

In our models we employ an effective viscosity law combining both Newtonian and Non-Newtonian power laws with a pseudo-plastic model. We study the influence of rheology in combination with grain size and different yield stress parameterizations on the likelihood of the on-set of plate tectonics in a 2D-spherical annulus geometry. We compute common diagnostic values related to the characterization of a mobilized surface. With this model we aim at identifying key planetary factors for the occurrence or absence of plate tectonics.

Author(s): Philipp Baumeister (1,2), Nicola Tosi (1), Caroline Brachmann (1), John Lee Greenfell (1), Jasmine MacKenzie (2)

Affiliation: (1) German Aerospace Center (DLR) Berlin, Germany, (2) Technische Universität Berlin, Germany

Abstract:

A major goal in exoplanet science is the search for planets with the right conditions to support liquid water (1). The habitability of a planet depends strongly on the composition of its atmosphere. Meanwhile, the interior and atmosphere of rocky planets are intricately linked through feedback processes and consequently evolve as a coupled system. In particular, volcanic outgassing of volatile species from the planet’s silicate mantle shapes the atmospheric composition, temperature, and pressure, but the exact composition of outgassed species not only depends on the volatile content and redox state of the mantle, but also on the current state of the atmosphere (2, 3). This means that the interior dynamics of planets can not be neglected, especially since much of the surface water on terrestrial planets originates from the planetary mantle.

In an extensive parameter study of rocky exoplanets, we investigated the emergence of habitable surface conditions for a wide range of initial conditions, including the planet mass, interior structure, volatile content and redox state, as well as the distance of the planet to its host star. The model accounts for the main mechanisms controlling the global-scale, long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics), and it includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as escape processes of H2.

We find that only a narrow range of the mantle redox state around the iron-wüstite buffer allows forming atmospheres that lead to long-term habitable conditions. At more oxidizing conditions, most planets instead end up in a runaway greenhouse state (akin to Venus) due to strong CO2 outgassing. On the other hand, the amount of outgassed greenhouse gasses on planets with more reducing mantles is often too low to keep the surface above the freezing point of water.

References

1. Noack, L., Snellen, I. & Rauer, H. (2017) Space Sci Rev 212, 877–898.
2. Ortenzi, G. et al. (2020) Sci Rep 10, 10907.
3. Gaillard, F. & Scaillet, B. (2014) Earth and Planetary Science Letters 403, 307–316.

Author(s): Taylor, S.F.

Affiliation: (1) SETI Institute Affiliate (2) Participation Worldscope

Abstract:

The gap in the solar system’s proto-planetary disks (SS’s PPD) confirms the prediction that PPDs must have precursors to the peak-gap-peak (PGP) feature in the distribution of planets of stars most like the sun. The SS’s PPD was closer than 3 AU compared to 1.9 AU from the star for the gap-peak boundary of the PGP. The location of this GP boundary scales with the square root of the stellar mass, so it must have been created when the proto-stellar luminosity was proportional to the stellar mass. Though the PGP is already statistically strongly unlikely to have occurred by random, finding additional physical characteristics of this PGP further evidences that it is a major feature of essential importance for understanding planet formation.

References

Taylor, S.F., 2019, “Unexpected gap creating two peaks … of metal-rich sunlike single stars”, Astron. Nach., 2019, DOI:10.1002/asna.201913497.

Borlina, C.S.; et al..; “Paleomagnetic Evidence for a Disk Substructure in the Early Solar System.” Science Adv 7, no. 42 (2021): eabj6928. https://doi.org/10.1126/sciadv.abj6928.

Taylor, S.F., 2021 “Peaks in … Exoplanets … Must Have Analogues in PPDs”, https://nexsci.caltech.edu/workshop/2021/posters/Poster_StuartFTaylor_98.jpg

Author(s): Antranik A. Sefilian

Affiliation: (1) DAMTP, University of Cambridge, UK; (2) AIU, University of Jena, Germany.

Abstract:

Spatially resolved images of debris discs frequently reveal complex morphologies such as gaps, spirals, and warps. Most existing dynamical models for explaining such morphologies focus on the role of (invoked) massive perturbers such as planets, ignoring the gravitational effects of the disc itself. This assumption, however, may not always be justified, especially in view of observations that debris discs could contain tens of Earth masses in large planetesimals. In this poster, I will present results showing that the (self-)gravitational potential of debris discs can be important for producing some of the observed disc structures. Namely, I will demonstrate that the long-term (i.e., secular) interaction between a single planet and an external, self-gravitating debris disc can lead to the formation of a wide gap within the disc. The proposed mechanism is based on the occurrence of secular resonances within the disc, which is found to be quite robust even when the disc is less massive than the planet. I will also show that the very same mechanism may lead to the launching of a long, one-armed spiral arm beyond the gap, while at the same time the planetary orbit circularises. Applications of these results for explaining observations will be discussed at length, with a focus on the implications for (i) inferring the presence and properties of yet-unseen planets and (ii) indirectly determining the total masses of debris discs.

Author(s): Katja Stock(1), Leonard Benkendorff(1), Maxwell Xu Cai(2), Rainer Spurzem(1,3), Francesco Flammini Dotti(1)

Affiliation: (1) Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany, (2) Leiden Observatory, Leiden University, The Netherlands, (3) Kavli Institute for Astronomy and Astrophysics, Peking University, P.R. China

Abstract:

Stars – and thus also their planets – are mainly formed in clustered environments. Due to the high stellar densities occurring there, close flybys of other stars are common, which can significantly alter the planetary orbits. We investigate whether star cluster birth environments can explain the phenomenon of Hot Jupiters (HJs) – massive planets very close to the central star. For this purpose, we simulate planetary systems with 4 and 5 Jupiter-like planets around Solar-like host stars in a star cluster with 64000 stars for a timescale of 100Myr. We find that stellar flybys can initiate a chain process of planet-planet scattering and high-eccentricity tidal migration that can result in the formation of a HJ.

Author(s): Francesco Flammini Dotti, M.B.N. (Thijs) Kouwenhoven, A. W. H. Kamlah, Rainer Spurzem

Affiliation: (1) University of Heidelberg, Germany (2) Xi’an Jiaotong-Liverpool University, China (3) Max Plank Institute for Astronomy, Heidelberg, Germany & University of Heidelberg, Germany (4) University of Heidelberg, Germany & Kavli Institute for Astronomy and Astrophysics at Peking University, China

Abstract:

Global rotation plays an important role in the dynamical evolution of star clusters. This momentum is transported to the outskirts of the star cluster and removed due to ejections and evaporation of stars. Here, we use direct N-body simulations to model the effect of global rotation on the dynamical evolution of stars and free-floating
planets (FFPs). We want to determine whether these components have a preferred ejection direction, and which mechanisms are the cause. Mass segregation seems to be a fundamental process for the dynamical evolution and direction of the ejection of stars, while FFPs are less affected by the global rotation and only subjected to the gravitational potential of the star cluster core. Larger initial angular velocities reduce the ejection rate of FFPs and stars. Stars are preferably ejected closer to the rotational plane, while the distribution of ejected FFPs is more isotropic.

Author(s): (1) Astronomisches Rechen-Institut, ZAH, Univ. Heidelberg; (2) Kavli Institute for Astronomy and Astrophysics, Peking University

Affiliation: (1) Astronomisches Rechen-Institut, ZAH, Univ. Heidelberg; (2) Kavli Institute for Astronomy and Astrophysics, Peking University

Abstract:

The birth places of many if not all stars – and their planetary systems, is a star cluster or association, which may either disperse after some time or remain an open cluster. The effect of stellar flybys in young star clusters on the survival, stability, and dynamics of planetary systems is reviewed. It provides an extra and complementary mechanism to explain the observed diversity of extrasolar planets. We study by numerical simulations the simultaneous evolution of star clusters and their planetary systems; due to the dynamic range and corresponding accuracy requirements this is challenging. Our current and possible future methods are presented and discussed.

Then a selected range of specific applications will be discussed, such as e.g. the creation and further fate of escaping planets (free floaters), formation of resonant systems, of hot jupiters or other special systems, planetary systems around evolved stars or compact remnants, and circumbinary planets of both types. Some of the topics will be presented in separate contributions here.

References

Davari, N., et al., Stability of planetary systems within the S-star cluster: the Solar system analogues, MNRAS 2022
Stock, K. et al., On the survival of resonant and non-resonant planetary systems in star clusters, MNRAS 2020
Flammini Dotti, F., et al., Planetary systems in a star cluster II: intermediate-mass black holes and planetary systems, MNRAS 2020
Spurzem, R., Giersz, M., Heggie, D. C., Lin, D. N. C., Dynamics of Planetary Systems in Star Clusters, ApJ 2009

Author(s): C. Swastik , [1, 2] Ravinder K. Banyal[1] , Mayank Narang , [3] P. Manoj ,[ 3] T. Sivarani , [1 ]S. P. Rajaguru ,[ 1] Athira Unni,[1, 2] and Bihan Banerjee[3]

Affiliation: (1 ) Indian Institute of Astrophysics, Koramangala 2nd Block, Bangalore 560034, India :(2)Pondicherry University, R.V. Nagar, Kalapet, 605014, Puducherry, India :(3)Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research Homi Bhabha Road, Colaba, Mumbai 400005, India

Abstract:

The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with \textbf{older generation} stars showing higher $\alpha$-element abundances while the later generations becoming enriched with iron-peak elements. The evolutionary connections and chemical characteristics of circumstellar disks, stars, and their planetary companions can be inferred by studying the interdependence of planetary and host star properties. Numerous studies in the past have confirmed that high-mass giant planets are commonly found around metal-rich stars, while the stellar hosts of low-mass planets have a wide range of metallicity. In this work, we analyzed the detailed chemical abundances for a sample of $>900$ exoplanet hosting stars drawn from different radial velocity and transit surveys. We correlate the stellar abundance trends for $\alpha$ and iron-peak elements with the planets‘ mass. We find the \textit{planet mass-abundance} correlation to be primarily negative for $\alpha$-elements and marginally positive or zero for the iron-peak elements, indicating that stars hosting giant planets are relatively younger. This is further validated by the age of the host stars obtained from isochrone fitting. The later enrichment of protoplanetary material with iron and iron-peak elements is also consistent with the formation of the giant planets via the core accretion process. A higher metal fraction in the protoplanetary disk is conducive to rapid core growth, thus providing a plausible route for the formation of giant planets. This study, therefore, indicates the observed trends in stellar abundances and planet mass are most likely a natural consequence of Galactic chemical evolution.

References

Reference : https://arxiv.org/abs/2205.15793?context=astro-ph

Author(s): Grzegorz Musiolik

Affiliation: German Space Agency (DLR), Germany

Abstract:

In Protoplanetary Discs (PPDs), the growth of aggregates by Hit&Stick collisions is interrupted at the bouncing barrier. Different mechanisms have been introduced in the past to explain the growth of aggregates beyond the bouncing barrier, e.g. due to magnetorotational instabilities, collisions of „lucky winners“, tribocharging effects, or due to collisions of aggregates coated with ice.

We study collisions of aggregates with a liquid-like H2O–CH3OH–NH3 ice shell numerically in this work. H2O–CH3OH–NH3-ice behaves liquid-like when UV irradiated within a PPD-like environment. Sticking collisions of aggregates coated by this species of liquid-like ice might lead to overcome the bouncing barrier.

The coefficient of restitution and the sticking velocity are calculated for different thicknesses of the ice shell. The simulation predicts that a liquid-like H2O–CH3OH–NH3-shell of few microns might enable the growth of cm-sized clusters in the PPD.

Author(s): Sara Khalafinejad (1), Elias Hühn (1), Karan MolaverdiKhani (2), Lisa Nortmann (3), Andreas Quirrenbach (1), et. al

Affiliation: (1) Landessternwarte, Heidelberg University, Germany, (2) Universitäts-Sternwarte, Munich University, Germany, (3) Institute for Astrophysics, Göttingen University, Germany

Abstract:

High-resolution narrow-band transmission spectroscopy is a powerful technique for revealing the composition of the exoplanets and understanding further properties of their atmospheres. With this technique, in the optical region, sodium is one of the most commonly detected features in the upper atmosphere of giant hot exoplanets. In addition, in the IR part of the spectrum, detection of helium features has been in the focus. This research presents homogeneous narrow-band transmission spectroscopy of 5 giant exoplanets in the Na and He regions, obtained using CARMENES instrument. For obtaining a complete picture of the atmosphere, our results are/will be merged with low-resolution transmission spectra of various ground- and space-based instruments such as Magellan, HST, and JWST telescopes.

Author(s): Filip Matuszewski (1), Nadine Nettelmann (1), Juan Cabrera (1), Anko Börner (2), and Heike Rauer (1,3,4)

Affiliation: (1) Institute of Planetary Research, German Aerospace Center, Germany, (2) Institute of Optical Sensor Systems, German Aerospace Center, Germany, (3) Department of Geological Sciences, Freie Universität Berlin, Germany, (4) Center for Astronomy and Astrophysics, Technical University Berlin, Germany

Abstract:

The PLATO mission, scheduled to launch in 2026, will monitor more than 245.000 FGK stars (P5 sample) of magnitude 13 or brighter to search for planet transit events [1]. Among its scientific goals are constraining planet formation models, detecting Earth-sized planets in the HZ of Sun-like stars, and determining planet occurrence rates [1].

Here, we estimate the number of exoplanets that PLATO can detect as a function of planetary size and period, stellar brightness, as well as observing strategy options by adopting a statistical approach. We apply given occurrence rates from planet formation models [2], and from different search and vetting pipelines for Kepler-data [3,4] and represent the stellar sample to be observed by a fraction of the PLATO all-sky stellar input catalogue [5].

We find that the expected PLATO planet yield increases rapidly over the first year and begins to saturate after 2 yrs. A nominal (2+2yr) 4-year mission could yield about several 1000 to several 10000 planets, depending on the assumed planet occurrence rates. We estimate a minimum of 500 Earth-sized (0.8–1.25 RE) planets, out of which about a dozen would reside in a 250-500d period bin around G-stars. A 3 year long observation followed by 6 two month short observations (3+1yr) yield roughly twice as many planets as two long observations of 2 years (2+2yr). The former strategy is dominated by short period planets while the latter is more beneficial for detecting Earths in the habitable zone.

References

1. PLATO Definition Study Report (2017), ESA-SCI(2017)1

2. Emsenhuber A. et al (2021), AA 656:A70

3. Hsu D.C. et al. (2019) 158:109

4. Kunimoto M. and Matthews J.M. (2020) AJ 159:248

5. Montalto M. et al (2021), AA 653:A98

Author(s): S. Ulmer-Moll (1), M. Lendl (1), S. Gill (2), S. Villanueva (3), M. Hobson (4), C. Mordasini (5), F. Bouchy (1)

Affiliation: (1) Geneva, Geneva Observatory, Astronomy, Switzerland, (2) Department of physics, University of Warwick, Gibbet hill road, Coventry CV4 7AL, UK, (3) Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, (4) Millennium Institute for Astrophysics, Chile, (5) Physikalisches Institut, University of Bern, Gesellschaftsstrasse 6, 3012 Bern, Switzerland

Abstract:

Warm Jupiters provide a unique opportunity to better understand the formation and evolution of planetary systems. Their atmospheric properties remain largely unaltered by the impact of the host star, and their orbital arrangement reflects a different, and less extreme, migrational history compared to close-in objects. Warm Jupiters are known to cover a wide range of eccentricities but it is unclear which are the dominant formation pathways to explain this observation. Increasing the sample of long-period exoplanets with known radii is thus crucial. In this talk, I report the results of a survey set out to find transiting giants with orbital periods between 20 and 200 days (Ulmer-Moll et al., 2022). We selected 50 stars which show a single transit in one TESS sector (27d baseline) and followed them with ground-based photometric and radial velocity facilities (e.g. NGTS, HARPS). After one year of observations, we report the detection and characterization of ten new transiting warm Jupiters, increasing by 50% the number of known warm Jupiters with precise masses and radii. We infer the metal enrichment of the newly discovered warm Jupiters and explore their influence on the mass-metallicity correlation of giant planets. The growing sample of warm Jupiters allows us to interpret these systems in terms of planet formation models. Finally, these targets orbit bright stars and thus are ideal for follow-up studies of the planetary atmosphere and the system‘ spin-orbit alignment. This work is a stepping stone for PLATO, as identification and follow up of single transit events will be key in order to detect transiting Earth-sized planets in the habitable zone of Sun-like stars.

References

Ulmer-Moll, S., et al. (2022), A&A, accepted, arXiv:2207.03911