Planet formation and disk mass dependence in a pebble-driven scenario for low mass stars

Abstract

Measured disk masses seem to be too low to form the observed population of planetary systems. In this context, we develop a population synthesis code in the pebble accretion scenario, to analyse the disk mass dependence on planet formation around low mass stars. We base our model on the analytical sequential model presented in Ormel et al. 2017 and analyse the populations resulting from varying initial disk mass distributions. Starting out with seeds the mass of Ceres near the ice-line formed by streaming instability, we grow the planets using the Pebble Accretion process and migrate them inwards using Type-I migration. The next planets are formed sequentially after the previous planet crosses the ice-line. We explore different initial distributions of disk masses to show the dependence of this parameter with the final planetary population. Our results show that compact close-in resonant systems can be pretty common around M-dwarfs between $0.09-0.2$ $M_{\odot }$ only when the disks considered are more massive than what is being observed by sub-mm disk surveys. The minimum disk mass to form a Mars-like planet is found to be about $2\times 10^{-3}$ $M_{\odot }$. Small variation in the disk mass distribution also manifest in the simulated planet distribution. The paradox of disk masses might be caused by an underestimation of the disk masses in observations, by a rapid depletion of mass in disks by planets growing within a million years or by deficiencies in our current planet formation picture.

Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal on 29th September 2020

References in corpus (10)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering
• Grain growth in the envelopes and disks of Class I protostars
• Formation and composition of planets around very low mass stars
• A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs
• Planetesimal Population Synthesis: Pebble Flux Regulated Planetesimal Formation
• Pebble-driven Planet Formation around Very Low-mass Stars and Brown Dwarfs
• The HARPS search for southern extra-solar planets XLII. A system of Earth-mass planets around the nearby M dwarf YZ Ceti
• Pebbles versus planetesimals: the outcomes of population synthesis models

Cited by in corpus (2)

• Understanding planet formation using microgravity experiments
• Formation of multiple-planet systems in resonant chains around M dwarfs