A framework for the architecture of exoplanetary systems. II. Nature versus nurture: Emergent formation pathways of architecture classes

Mishra, Lokesh; Alibert, Yann; Udry, S.; Mordasini, Christoph

doi:10.48550/arxiv.2301.02373

Cited by 2 publications

(6 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…14 and the bottom right panel of Fig. 2 of Mishra et al [145] reveals the nevertheless existing correspondence between our classification and theirs. We note that, broadly speaking, the 'similar' class of Mishra et al [145] corresponds to our Class I and II.…”

Section: Architecture Classsupporting

confidence: 70%

“…2 of Mishra et al [145] reveals the nevertheless existing correspondence between our classification and theirs. We note that, broadly speaking, the 'similar' class of Mishra et al [145] corresponds to our Class I and II. Also, our Class III systems correspond to 'mixed' systems and a part of the 'ordered' ones, while Class IV corresponds to the other part of 'ordered' systems and the 'anti-ordered' ones.…”

Section: Architecture Classsupporting

confidence: 70%

“…This approach stresses the temporal emergence of system architectures and the underlying physical processes included in the theoretical model. This is in contrast with the approach of Mishra et al [144,145], who classified the systems based on the observable present day properties of the final systems.…”

Section: Discussionmentioning

confidence: 87%

“…Our approach thus stresses the temporal emergence of different system architectures and the (theoretical) physical mechanisms included in the model leading to them. A distinct approach was recently presented by Mishra et al [144,145] who also classified the population used here in four distinct types. Their analysis is focused on observable systems, by applying observational biases on the final systems.…”

Section: Four Classes Of System Architecturesmentioning

confidence: 99%

“…The classification by Mishra et al [144,145] was applied to the same synthetic data as our approach. It is a complementary approach since, in contrast with our human-based approach (that stresses underlying physical processes and the emergence of planetary system architecture in time), it can be applied to observational data without knowledge of the formation history of the systems or the underlying formation processes.…”

Section: Architecture Classmentioning

confidence: 99%

See 4 more Smart Citations

Planetary population synthesis and the emergence of four classes of planetary system architectures

2023

Self Cite

View full text Add to dashboard Cite

Planetary population synthesis is a helpful tool to understand the physics of planetary system formation. It builds on a global model, meaning that the model has to include a multitude of physical processes. The outcome can be statistically compared with exoplanet observations. Here, we review the population synthesis method and then use one population computed using the Generation III Bern model to explore how different planetary system architectures emerge and which conditions lead to their formation. The emerging systems can be classified into four main architectures: Class I of near in situ compositionally ordered terrestrial and ice planets, Class II of migrated sub-Neptunes, Class III of mixed low-mass and giant planets, broadly similar to the Solar System, and Class IV of dynamically active giants without inner low-mass planets. These four classes exhibit distinct typical formation pathways and are characterised by certain mass scales. We find that Class I forms from the local accretion of planetesimals followed by a giant impact phase, and the final planet masses correspond to what is expected from such a scenario, the ‘Goldreich mass’. Class II, the migrated sub-Neptune systems form when planets reach the ‘equality mass’ where accretion and migration timescales are comparable before the dispersal of the gas disc, but not large enough to allow for rapid gas accretion. Giant planets form when the ‘equality mass’ allows for gas accretion to proceed while the planet is migrating, i.e. when the critical core mass is reached. The main discriminant of the four classes is the initial mass of solids in the disc, with contributions from the lifetime and mass of the gas disc. The distinction between mixed Class III systems and Class IV dynamically active giants is in part due to the stochastic nature of dynamical interactions, such as scatterings between giant planets, rather than the initial conditions only. The breakdown of system into classes allows to better interpret the outcome of a complex model and understand which physical processes are dominant. Comparison with observations reveals differences to the actual population, pointing at limitation of theoretical understanding. For example, the overrepresentation of synthetic super-Earths and sub-Neptunes in Class I systems causes these planets to be found at lower metallicities than in observations.

show abstract

Section: Architecture Classsupporting

confidence: 70%

Section: Architecture Classsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 87%

Section: Four Classes Of System Architecturesmentioning

confidence: 99%

Section: Architecture Classmentioning

confidence: 99%

See 3 more Smart Citations

Planetary population synthesis and the emergence of four classes of planetary system architectures

2023

Self Cite

View full text Add to dashboard Cite

show abstract

LHS 1903 provides evidence for gas-depleted formation of planets around M-dwarfs

Wilson,

Simpson,

Cameron

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

Many important advances in planet formation theory have come from the discovery of unexpected planets. The thousands of discovered exoplanets have unveiled demographic trends, such as the bimodality of planetary radius distribution known as the radius valley. Modelling these trends can probe underlying processes, e.g. the formation environment and atmospheric evolution. Here, we report the discovery and characterisation of a four-planet system around the kinematically thick-disk M-dwarf LHS 1903 with orbital periods of 2.16, 6.23, 12.57, and 29.32 days that becomes the only known M-dwarf hosting four small, well-characterised planets spanning the radius valley. We utilise high-precision transit photometry from the Transiting Exoplanet Survey Satellite (TESS) and the CHaracterising ExOPlanets Satellite (CHEOPS) to measure the radii of LHS 1903 b, c, d, and e (1.382+/-0.046, 2.046^+0.078_-0.074, 2.500^+0.078_-0.077, and 1.732^+0.059_-0.058 R_oplus). Combined with HARPS-N radial velocity data, we determine the planetary bulk densities (1.24^+0.21_-0.19, 0.53^+0.11_-0.09, 0.38^+0.09_-0.08, and 1.11^+0.33_-0.31 rho_oplus). Our compositional analysis finds that planet b is rocky, planets c and d have extended atmospheres, and LHS 1903 e does not have a gaseous envelope. Our discovery that planet e, the longest-period well-characterised terrestrial M-dwarf planet, lacks an extended atmosphere causes tension with thermally-driven mass loss radius valley predictions, but supports a gas-depleted formation explanation. The observed broken atmospheric-mass fraction trend is at odds with current formation theory, but provides further evidence for a gas-depleted formation environment for terrestrial M-dwarf planets.

show abstract

A framework for the architecture of exoplanetary systems. II. Nature versus nurture: Emergent formation pathways of architecture classes

Cited by 2 publications

References 69 publications

Planetary population synthesis and the emergence of four classes of planetary system architectures

Planetary population synthesis and the emergence of four classes of planetary system architectures

LHS 1903 provides evidence for gas-depleted formation of planets around M-dwarfs

Contact Info

Product

Resources

About