Super-Earth Atmospheres: Self-Consistent Gas Accretion and Retention

@article{Ginzburg2015SuperEarthAS,
  title={Super-Earth Atmospheres: Self-Consistent Gas Accretion and Retention},
  author={Sivan Ginzburg and Hilke E. Schlichting and Re’em Sari},
  journal={arXiv: Earth and Planetary Astrophysics},
  year={2015}
}
Some recently discovered short-period Earth to Neptune sized exoplanets (super Earths) have low observed mean densities which can only be explained by voluminous gaseous atmospheres. Here, we study the conditions allowing the accretion and retention of such atmospheres. We self-consistently couple the nebular gas accretion onto rocky cores and the subsequent evolution of gas envelopes following the dispersal of the protoplanetary disk. Specifically, we address mass-loss due to both photo… Expand

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References

SHOWING 1-10 OF 49 REFERENCES
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,Expand
Atmospheres of Protoplanetary Cores: Critical Mass for Nucleated Instability
We systematically study quasi-static atmospheres of accreting protoplanetary cores for different opacity behaviors and realistic planetesimal accretion rates in various parts of the protoplanetaryExpand
Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
Close-in super-Earths having radii 1--4 $R_\oplus$ may possess hydrogen atmospheres comprising a few percent by mass of their rocky cores. We determine the conditions under which such atmospheres canExpand
Atmospheres of low-mass planets: the "boil-off"
We show that, for a low-mass planet that orbits its host star within a few tenths of an AU (like the majority of the {\it Kepler} planets), the atmosphere it was able to accumulate while embedded inExpand
Hydrodynamics of embedded planets’ first atmospheres – I. A centrifugal growth barrier for 2D flows
In the core accretion paradigm of planet formation, gas giants only form a massive atmosphere after their progenitors exceeded a threshold mass: the critical core mass. Most (exo)planets, beingExpand
The formation of super-Earths and mini-Neptunes with giant impacts
The majority of discovered exoplanetary systems harbour a new class of planets, bodies that are typically several times more massive than the Earth but that orbit their host stars well inside theExpand
FORMATION AND STRUCTURE OF LOW-DENSITY EXO-NEPTUNES
Kepler has found hundreds of Neptune-size (2-6 R{sub +}) planet candidates within 0.5 AU of their stars. The nature of the vast majority of these planets is not known because their masses have notExpand
Formation of close in Super-Earths \& Mini-Neptunes: Required Disk Masses \& Their Implications
Recent observations by the {\it Kepler} space telescope have led to the discovery of more than 4000 exoplanet candidates consisting of many systems with Earth- to Neptune-sized objects that resideExpand
Hydrodynamics of embedded planets' first atmospheres - II. A rapid recycling of atmospheric gas
Following Paper I we investigate the properties of atmospheres that form around small protoplanets embedded in a protoplanetary disc by conducting hydrodynamical simulations. These are now extendedExpand
ON THE MINIMUM CORE MASS FOR GIANT PLANET FORMATION AT WIDE SEPARATIONS
In the core accretion hypothesis, giant planets form by gas accretion onto solid protoplanetary cores. The minimum (or critical) core mass to form a gas giant is typically quoted as 10 M ⊕. TheExpand
...
1
2
3
4
5
...