Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system

Ogihara, Masahiro; Kokubo, Eiichiro; Nakano, R.; Suzuki, Takeru

doi:10.1051/0004-6361/202142354

Cited by 6 publications

(3 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Planets b and c would have grown close to the star, possibly at their present-day location. On the other hand, planets d-h would have grown farther from the star than their current location (Ormel et al 2017;Coleman et al 2019;Huang & Ormel 2022;Ogihara et al 2022). They could have migrated inward to their present-day location after formation.…”

Section: Discussionmentioning

confidence: 98%

Formation of the Trappist-1 system in a dry protoplanetary disk

Schneeberger,

Mousis,

Deleuil

et al. 2024

A&A

View full text Add to dashboard Cite

A key feature of the Trappist-1 system is its monotonic decrease in bulk density with growing distance from the central star, which indicates an ice mass fraction that is zero in the innermost planets, b and c, and about 10<!PCT!> in planets d through h. Previous studies suggest that the density gradient of this system could be due to the growth of planets from icy planetesimals that progressively lost their volatile content during their inward drift through the protoplanetary disk. Here we investigate the alternative possibility that the planets formed in a dry protoplanetary disk populated with pebbles made of phyllosilicates, a class of hydrated minerals with a water fraction possibly exceeding 10 wt<!PCT!>. We show that the dehydration of these minerals in the inner regions of the disk and the outward diffusion of the released vapor up to the ice-line location allow the condensation of ice onto grains. Pebbles with water mass fractions consistent with those of planets d--h would have formed at the snow-line location. In contrast, planets b and c would have been accreted from drier material in regions closer to the star than the phyllosilicate dehydration line.

show abstract

Section: Discussionmentioning

confidence: 98%

Formation of the Trappist-1 system in a dry protoplanetary disk

Schneeberger,

Mousis,

Deleuil

et al. 2024

A&A

View full text Add to dashboard Cite

show abstract

“…The formation of the TRAPPIST-1 planets is not yet well understood, but recent studies point to a potential combination of pebble accretion and planet migration (Ormel et al 2017;Unterborn et al 2018;Schoonenberg et al 2019) possibly followed by rebound because of the dispersion of the disc as well as tidal dissipation in the planets (Huang & Ormel 2022). An alternative scenario relies on different modes of migration (Ogihara et al 2022). As the planets migrate through the disc towards the star they will encounter mutual meanmotion resonances (e.g.…”

Section: Basic Outline Of Resonant Trappingmentioning

confidence: 99%

Long-term tidal evolution of the TRAPPIST-1 system

Brasser

Pichierri

Dobos

et al. 2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The ultracool M-dwarf star TRAPPIST-1 is surrounded by seven planets configured in a resonant chain. Transit-timing variations have shown that the planets are caught in multiple three-body resonances and that their orbits are slightly eccentric, probably caused by resonant forcing. The current values of the eccentricities could be a remnant from their formation. Here we run numerical simulations using fictitious forces of trapping the fully-grown planets in resonances as they migrated in the gas disc, followed by numerical simulations detailing their tidal evolution. For a reduced disc scale height h ∼ 0.03–0.05, the eccentricities of the planets upon capture in resonance are higher than their current values by factors of a few. We show that the current eccentricities and spacing of planets d to h are natural outcomes of coupled tidal evolution wherein the planets simultaneously damp their eccentricities and separate due to their resonant interaction. We further show that the planets evolve along a set of equilibrium curves in semimajor axis–eccentricity phase space that are defined by the resonances, and that conserve angular momentum. As such, the current 8:5–5:3–(3:2)2–4:3–3:2 resonant configuration cannot be reproduced from a primordial (3:2)4–4:3–3:2 resonant configuration from tidal dissipation in the planets alone. We use our simulations to constrain the long-term tidal parameters k2/Q for planets b to e, which are in the range 10−3 to 10−2, and show that these are mostly consistent with those obtained from interior modelling following reasonable assumptions.

show abstract

“…In this way the amount of solid material for planet formation is low enough so that the planet does not reach the stage of rapid gas accretion before the disk dissipates (Pollack et al 1996;Alibert et al 2005;Frelikh & Murray-Clay 2017). In addition, the protoplanetary embryo remains small enough while the gas is in place, so that migration is not an issue (Armitage 2020;Ogihara et al 2022). In the case of pebble accretion things will happen more quickly, and we address this in Section 5.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Accretion Rate and Composition on the Structure of Ice-rich Super-Earths

Lozovsky

Prialnik

Podolak

2022

ApJ

View full text Add to dashboard Cite

It is reasonable to assume that the structure of a planet and the interior distribution of its components are determined by its formation history. We thus follow the growth of a planet from a small embryo through its subsequent evolution. We estimate the accretion rate range based on a protoplanetary disk model at a large-enough distance from the central star for water ice to be a major component. We assume the accreted material to be a mixture of silicate rock and ice, with no H–He envelope, as the accretion timescale is much longer than the time required for the nebular gas to dissipate. We adopt a thermal evolution model that includes accretional heating, radioactive energy release, and separation of ice and rock. Taking the Safronov parameter and the ice-to-rock ratio as free parameters, we compute growth and evolutionary sequences for different parameter combinations, for 4.6 Gyr. We find the final structure to depend significantly on both parameters. Low initial ice-to-rock ratios and high accretion rates, each resulting in an increased heating rate, lead to the formation of extended rocky cores, while the opposite conditions leave the composition almost unchanged and result in relatively low internal temperatures. When rocky cores form, the ice-rich outer mantles still contain rock mixed with the ice. We find that a considerable fraction of the ice evaporates upon accretion, depending on parameters, and assume it is lost, thus the final surface composition and bulk density of the planet do not necessarily reflect the protoplanetary disk composition.

show abstract

Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system

Cited by 6 publications

References 44 publications

Formation of the Trappist-1 system in a dry protoplanetary disk

Formation of the Trappist-1 system in a dry protoplanetary disk

Long-term tidal evolution of the TRAPPIST-1 system

The Effect of Accretion Rate and Composition on the Structure of Ice-rich Super-Earths

Contact Info

Product

Resources

About