The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution

Context. The search for extrasolar planets has been limited so far to close orbit (typ. ≤5 au) planets around mature solar-type stars on the one hand, and to planets on wide orbits (≥10 au) around young stars on the other hand. To get a better view of the full giant planet population, we have started a survey to search for giant planets around a sample of carefully selected young stars. Aims. This paper aims at exploring the giant planet population around one of our targets, β Pictoris, over a wide range of separations. With a disk and a planet already known, the β Pictoris system is indeed a very precious system for studies of planetary formation and evolution, as well as of planet–disk interactions. Methods. We analyse more than 2000 HARPS high-resolution spectra taken over 13 years as well as NaCo images recorded between 2003 and 2016. We combine these data to compute the detection probabilities of planets throughout the disk, from a fraction of au to a few dozen au. Results. We exclude the presence of planets more massive than 3 MJup closer than 1 au and further than 10 au, with a 90% probability. 15+ MJup companions are excluded throughout the disk except between 3 and 5 au with a 90% probability. In this region, we exclude companions with masses larger than 18 (resp. 30) MJup with probabilities of 60 (resp. 90) %.

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How many suns are in the sky? Multiplicity surveys of exoplanet host stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319001595 ◽

2018 ◽

Vol 14 (S345) ◽

pp. 316-317 ◽

Cited By ~ 1

Author(s):

M. Mugrauer ◽

C. Ginski ◽

N. Vogt ◽

R. Neuhäuser ◽

C. Adam

Keyword(s):

Milky Way ◽

Planet Formation ◽

High Contrast ◽

Contrast Imaging ◽

Direct Imaging ◽

High Contrast Imaging ◽

Multiple Stars ◽

First Results ◽

Formation And Evolution ◽

Host Stars

AbstractIn order to determine the true impact of stellar multiplicity on the formation and evolution of planets, we initiated direct imaging surveys to search for (sub)stellar companions of exoplanet host stars on close orbits, as their gravitational impact on the planet bearing disk at first and on formed planets afterwards is expected to be maximal. According to theory these are the most challenging environments for planet formation and evolution but might occur quite frequently in the milky way, due to the large number of multiple stars within our galaxy. On this poster we showed results, obtained so far in the course of our AO and Lucky-imaging campaigns of exoplanet host stars, conducted with NACO/ESO-VLT for southern and with AstraLux/CAHA2.2m for northern targets, respectively. In addition, we introduced our new high contrast imaging survey with SPHERE/ESO-VLT to search for close companions of southern exoplanet host stars, and presented some first results.

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Water worlds in N-body simulations with fragmentation in systems without gaseous giants

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037619 ◽

2020 ◽

Vol 641 ◽

pp. A139

Author(s):

A. Dugaro ◽

G. C. de Elía ◽

L. A. Darriba

Keyword(s):

Realistic Model ◽

Habitable Zone ◽

Minimum Mass ◽

Dynamical Friction ◽

Solar Type ◽

Formation And Evolution ◽

Hit And Run ◽

The Individual ◽

Very High ◽

Water Contents

Aims. We analyze the formation and evolution of terrestrial-like planets around solar-type stars in the absence of gaseous giants. In particular, we focus on the physical and dynamical properties of those that survive in the system’s habitable zone (HZ). This investigation is based on a comparative study between N-body simulations that include fragmentation and others that consider all collisions as perfect mergers. Methods. We use an N-body code, presented in a previous paper, that allows planetary fragmentation. We carry out three sets of 24 simulations for 400 Myr. Two sets are developed adopting a model that includes hit-and-run collisions and planetary fragmentation, each one with different values of the individual minimum mass allowed for the fragments. For the third set, we considered that all collisions lead to perfect mergers. Results. The planetary systems produced in N-body simulations with and without fragmentation are broadly similar, though with some differences. In simulations with fragmentation, the formed planets have lower masses since part of them is distributed among collisional fragments. Additionally, those planets presented lower eccentricities, presumably due to dynamical friction with the generated fragments. Lastly, perfect mergers and hit-and-run collisions are the most common outcome. Regardless of the collisional treatment adopted, most of the planets that survive in the HZ start the simulation beyond the snow line, having very high final water contents. Such planets are called water worlds. The fragments’ contribution to their final mass and water content is negligible. Finally, the individual minimum mass for fragments may play an important role in the planets’ collisional history. Conclusions. Collisional models that incorporate fragmentation and hit-and-run collisions lead to a more detailed description of the physical properties of the terrestrial-like planets formed. We conclude that planetary fragmentation is not a barrier to the formation of water worlds in the HZ. The results shown in this work suggest that further refinement is necessary to have a more realistic model of planetary formation.

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Characterisation of exoplanet host stars: A window into planet formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317006421 ◽

2017 ◽

Vol 12 (S330) ◽

pp. 369-376 ◽

Cited By ~ 1

Author(s):

Nuno C. Santos

Keyword(s):

Planet Formation ◽

The Sun ◽

The Future ◽

The Galaxy ◽

Crucial Information ◽

Formation And Evolution ◽

Host Stars

AbstractThe detection of thousands of planets orbiting stars other than the Sun has shown that planets are common throughout the Galaxy. However, the diversity of systems found has also raised many questions regarding the process of planet formation and evolution. Interestingly, but perhaps not unexpectedly, crucial information to constraint the planet formation models comes from the analysis of the planet-host stars. In this talk I will review why it is so important to study and understand the stars when finding and characterising exoplanets. I will then present some of the most relevant star-planet relations found to date, and how they are helping us to understand planet formation and evolution. I will end with a presentation of the future steps in this field, including what Gaia will bring to help constrain the properties of planet-host stars, as well as to the star-planet connection.

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Planet Formation in Transition Discs

10.5194/epsc2020-765 ◽

2020 ◽

Author(s):

Daniel Cummins ◽

James Owen

Keyword(s):

Large Scale ◽

Planet Formation ◽

Formation Processes ◽

Primary Interest ◽

Rapid Formation ◽

Planetary Embryo ◽

Large Scale Vortex ◽

Resolution Imaging ◽

Formation And Evolution ◽

The Impact

High-resolution imaging of protoplanetary discs has revealed their wealth of substructure. Perhaps the most striking observation has been the presence of large-scale crescent-shaped features, which have been interpreted as large quantities of dust trapped in anticyclonic vortices. Such regions of high dust-to-gas ratios are expected to promote planet formation processes, so understanding their formation and evolution is of primary interest. Gas-only hydrodynamics simulations have demonstrated that the thermal feedback from a planetary embryo undergoing rapid formation by pebble accretion can trigger the generation a large-scale vortex. However, the ability for such a vortex to trap dust and the impact this has on the forming planet are yet to be investigated. I will present results from hydrodynamics simulations of a disc containing both gas and dust, showing the efficiency with which dust grains accumulate in a vortex, and discuss the consequences this has for the growth of the planetary embryo.

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Abundances in Stars with Debris Disks

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313008934 ◽

2013 ◽

Vol 8 (S299) ◽

pp. 356-357

Author(s):

Adam M. Ritchey ◽

Guillermo Gonzalez ◽

Myra Stone ◽

George Wallerstein

Keyword(s):

Planet Formation ◽

Giant Planet ◽

Infrared Emission ◽

Stellar Atmospheres ◽

Elemental Abundance ◽

Condensation Temperature ◽

Debris Disks ◽

Chemical Abundance ◽

Preliminary Results ◽

Solar Type

AbstractWe present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Program, for the purpose of investigating whether the stellar atmospheres have been polluted with planetary material, which could indicate that the metallicity enhancement in stars with planets is due to metal-rich infall in the later stages of star and planet formation. The preliminary results presented here consist of precise abundances for 15 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Fe, Co, and Ni) for half of the stars in our sample. We find that none of the stars investigated so far exhibit the expected trend of increasing elemental abundance with increasing condensation temperature, which would result from the stars having accreted planetary debris. Rather, the slopes of linear least-squares fits to the abundance data are either negative or consistent with zero. In both cases, our results may indicate that, like the Sun, the debris disk host stars are deficient in refractory elements, a possible signature of terrestrial and/or gas giant planet formation.

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Methods for computing giant planet formation and evolution

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2004.08570.x ◽

2005 ◽

Vol 356 (4) ◽

pp. 1383-1395 ◽

Cited By ~ 10

Author(s):

O. G. Benvenuto ◽

A. Brunini

Keyword(s):

Planet Formation ◽

Giant Planet ◽

Formation And Evolution

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Six transiting planets and a chain of Laplace resonances in TOI-178

10.5194/epsc2021-811 ◽

2021 ◽

Author(s):

Adrien Leleu

Keyword(s):

Planet Formation ◽

Planetary Systems ◽

Single System ◽

Transiting Planets ◽

Orbital Configuration ◽

Resonant Systems ◽

Formation And Evolution ◽

A Chain ◽

Formation Phase

Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. As unveiled by TESS, CHEOPS, ESPRESSO, NGTS and SPECULOOS, TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, all planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet. TOI-178 have hence several characteristics that were not previously observed in a single system, making it a key system for the study of processes of formation and evolution of planetary systems. We will review what we know of TOI-178, and what we expect from futur observations.

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Physical properties of terrestrial planets and water delivery in the habitable zone using N-body simulations with fragmentation

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936061 ◽

2019 ◽

Vol 632 ◽

pp. A14 ◽

Cited By ~ 3

Author(s):

A. Dugaro ◽

G. C. de Elía ◽

L. A. Darriba

Keyword(s):

Terrestrial Planets ◽

Habitable Zone ◽

Water Delivery ◽

Class A ◽

Class B ◽

Solar Type ◽

Formation And Evolution ◽

Final Fraction ◽

The Masses ◽

Water Contents

Aims. The goal of this research is to study how the fragmentation of planetary embryos can affect the physical and dynamical properties of terrestrial planets around solar-type stars. Our study focuses on the formation and evolution of planets and water delivery in the habitable zone (HZ). We distinguish class A and class B HZ planets, which have an accretion seed initially located inside and beyond the snow line, respectively. Methods. We developed an N-body integrator that incorporates fragmentation and hit-and-run collisions, which is called D3 N-body code. From this, we performed 46 numerical simulations of planetary accretion in systems that host two gaseous giants similar to Jupiter and Saturn. We compared two sets of 23 N-body simulations, one of which includes a realistic collisional treatment and the other one models all impacts as perfect mergers. Results. The final masses of the HZ planets formed in runs with fragmentation are about 15–20% lower than those obtained without fragmentation. As for the class A HZ planets, those formed in simulations without fragmentation experience very significant increases in mass with respect to their initial values, while the growth of those produced in runs with fragmentation is less relevant. We remark that the fragments play a secondary role in the masses of the class A HZ planets, providing less than 30% of their final values. In runs without fragmentation, the final fraction of water of the class A HZ planets keeps the initial value since they do not accrete water-rich embryos. In runs with fragmentation, the final fraction of water of such planets strongly depends on the model used to distribute the water after each collision. The class B HZ planets do not show significant differences concerning their final water contents in runs with and without fragmentation. From this, we find that the collisional fragmentation is not a barrier to the survival of water worlds in the HZ.

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Extended stellar systems in the solar neighborhood

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037591 ◽

2020 ◽

Vol 639 ◽

pp. A64 ◽

Cited By ~ 1

Author(s):

Sebastian Ratzenböck ◽

Stefan Meingast ◽

João Alves ◽

Torsten Möller ◽

Immanuel Bomze

Keyword(s):

Support Vector Machines ◽

White Dwarfs ◽

Planet Formation ◽

Dynamical Evolution ◽

Solar Neighborhood ◽

Support Vector ◽

Stellar Systems ◽

High Fidelity ◽

Vector Machines ◽

Formation And Evolution

Context. Nearby stellar streams carry unique information on the dynamical evolution and disruption of stellar systems in the Galaxy, the mass distribution in the disk, and they provide unique targets for planet formation and evolution studies. Recently, Meingast 1, a 120° stellar stream with a length of at least 400 pc, was dicovered. Aims. We aim to revisit the Meingast 1 stream to search for new members within its currently known 400 pc extent, using Gaia DR2 data and an innovative machine learning approach. Methods. We used a bagging classifier of one-class support vector machines with Gaia DR2 data to perform a 5D search (positions and proper motions) for new stream members. The ensemble was created by randomly sampling 2.4 million hyper-parameter realizations admitting classifiers that fulfill a set of prior assumptions. We used the variable prediction frequency resulting from the multitude of classifiers to estimate a stream membership criterion, which we used to select high-fidelity sources. We used the HR diagram and the Cartesian velocity distribution as test and validation tools. Results. We find about 2000 stream members with high fidelity, or about an order of magnitude more than previously known, unveiling the stream’s population across the entire stellar mass spectrum, from B stars to M stars, including white dwarfs. We find that, apart from being slightly more metal poor, the HRD of the stream is indistinguishable from that of the Pleiades cluster. For the mass range at which we are mostly complete, ∼0.2 M⊙ < M < ∼4 M⊙, we find a normal IMF, allowing us to estimate the total mass of stream to be about 2000 M⊙, making this relatively young stream by far the most massive one known. In addition, we identify several white dwarfs as potential stream members. Conclusions. The nearby Meingast 1 stream, due to its richness, age, and distance, is a new fundamental laboratory for star and planet formation and evolution studies for the poorly studied and gravitationally unbound star formation mode. We also demonstrate that one-class support vector machines can be effectively used to unveil the full stellar populations of nearby stellar systems with Gaia data.

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