Unified Simulations of Planetary Formation and Atmospheric Evolution: Effects of Pebble Accretion, Giant Impacts, and Stellar Irradiation on Super-Earth Formation

@article{Ogihara2020UnifiedSO,
  title={Unified Simulations of Planetary Formation and Atmospheric Evolution: Effects of Pebble Accretion, Giant Impacts, and Stellar Irradiation on Super-Earth Formation},
  author={Masahiro Ogihara and Yasunori Hori},
  journal={The Astrophysical Journal},
  year={2020}
}
A substantial number of super-Earths have been discovered, and atmospheres of transiting super-Earths have also been observed by transmission spectroscopy. Several lines of observational evidence indicate that most super-Earths do not possess massive H$_2$/He atmospheres. However, accretion and retention of less massive atmospheres on super-Earths challenge planet formation theory. We consider the following three mechanisms: (i) envelope heating by pebble accretion, (ii) mass loss during giant… 
Unified Simulations of Planetary Formation and Atmospheric Evolution. II. Rapid Disk Clearing by Photoevaporation Yields Low-mass Super-Earth Atmospheres
Super-Earths possess low-mass H$_2$/He atmospheres (typically less than 10% by mass). However, the origins of super-Earth atmospheres have not yet been ascertained. We investigate the role of rapid
Size Evolution of Close-in Super-Earths through Giant Impacts and Photoevaporation
The Kepler transit survey with follow-up spectroscopic observations has discovered numerous super-Earth sized planets and revealed intriguing features of their sizes, orbital periods, and their
Most super-Earths formed by dry pebble accretion are less massive than 5 Earth masses
Aims. The goal of this work is to study the formation of rocky planets by dry pebble accretion from self-consistent dust-growth models. In particular, we aim to compute the maximum core mass of a
Hydrogen Dominated Atmospheres on Terrestrial Mass Planets: Evidence, Origin and Evolution
The discovery of thousands of highly irradiated, low-mass, exoplanets has led to the idea that atmospheric escape is an important process that can drive their evolution. Of particular interest is the
Ejection of close-in super-Earths around low-mass stars in the giant impact stage
Context. Earth-sized planets were observed in close-in orbits around M dwarfs. While more and more planets are expected to be uncovered around M dwarfs, theories of their formation and dynamical
Atmospheric Erosion by Giant Impacts onto Terrestrial Planets: A Scaling Law for any Speed, Angle, Mass, and Density
We present a new scaling law to predict the loss of atmosphere from planetary collisions for any speed, angle, impactor mass, target mass, and body compositions, in the regime of giant impacts onto
A tale of planet formation: from dust to planets
The characterization of exoplanets and their birth protoplanetary disks have enormously advanced in the last decade. Benefited from that, our global understanding of the planet formation has been
The nature of the radius valley
The existence of a Radius Valley in the Kepler size distribution stands as one of the most important observational constraints to understand the origin and composition of exoplanets with radii
Constraining the entropy of formation from young transiting planet
Recently K2 and TESS have discovered transiting planets with radii between $\sim$ 5-10 R$_\oplus$ around stars with ages $<100$ Myr. These young planets are likely to be the progenitors of the
How dust fragmentation may be beneficial to planetary growth by pebble accretion
Context. Pebble accretion is an emerging paradigm for the fast growth of planetary cores. Pebble flux and pebble sizes are the key parameters used in the pebble accretion models. Aims. We aim to
...
...

References

SHOWING 1-10 OF 96 REFERENCES
Hydrodynamics of embedded planets’ first atmospheres – III. The role of radiation transport for super-Earth planets
The population of close-in super-Earths, with gas mass fractions of up to 10 per cent represents a challenge for planet formation theory: how did they avoid runaway gas accretion and collapsing to
IN SITU ACCRETION OF HYDROGEN-RICH ATMOSPHERES ON SHORT-PERIOD SUPER-EARTHS: IMPLICATIONS FOR THE KEPLER-11 PLANETS
Motivated by recent discoveries of low-density super-Earths with short orbital periods, we have investigated in situ accretion of H-He atmospheres on rocky bodies embedded in dissipating warm disks,
Formation of planetary systems by pebble accretion and migration: growth of gas giants
At least 30% of main sequence stars host planets with sizes of between 1 and 4 Earth radii and orbital periods of less than 100 days. We use N-body simulations including a model for gas-assisted
N-body simulations of planet formation via pebble accretion I: First Results
Context. Planet formation with pebbles has been proposed to solve a couple of long-standing issues in the classical formation model. Some sophisticated simulations have been done to confirm the
The distribution of heavy-elements in giant protoplanetary atmospheres: the importance of planetesimal-envelope interactions.
In the standard model for giant planet formation, the planetary growth begins with accretion of solids followed by a buildup of a gaseous atmosphere as more solids are accreted, and finally, by rapid
A reassessment of the in situ formation of close-in super-Earths
Context. A large fraction of stars host one or multiple close-in super-Earth planets. There is an active debate about whether these planets formed in situ or at greater distances from the central
How planets grow by pebble accretion
During their formation, planets form large, hot atmospheres due to the ongoing accretion of solids. It has been customary to assume that all solids end up at the center, constituting a “core” of
Enhanced atmospheric loss on protoplanets at the giant impact phase in the presence of oceans
TLDR
It is suggested that remnants of the noble-gas rich proto-atmosphere survived on Venus, but not on Earth, because most of the neon must have escaped from both planets’ atmospheres later to yield the observed ratio of neon to argon.
Formation of close-in super-Earths in evolving protoplanetary disks due to disk winds
Context. Planets with masses larger than about 0.1 M⊕ undergo rapid inward migration (type I migration) in a standard protoplanetary disk. Recent magnetohydrodynamical simulations revealed the
A Limit on Gas Accretion onto Close-in Super-Earth Cores from Disk Accretion
The core-accretion model predicts that planetary cores as massive as super-Earths undergo runaway gas accretion to become gas giants. However, the exoplanet census revealed the prevalence of
...
...