Hydrodynamics of embedded planets’ first atmospheres – I. A centrifugal growth barrier for 2D flows

Ormel, Chris W.; Kuiper, Rolf; Shi, Ji-Ming

doi:10.1093/mnras/stu2101

Cited by 80 publications

(45 citation statements)

References 57 publications

(58 reference statements)

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“…The answer of Ormel et al (2014) (from here on referred to as Paper I), where we conducted 2D (planar) hydrodynamical simulations using the pluto code (Mignone et al 2007), to these questions is positive, consistent with earlier findings (Korycansky & Papaloizou 1996;Ormel 2013). Paper I also highlighted two features of embedded atmospheres.…”

Section: Introductionsupporting

confidence: 84%

Hydrodynamics of embedded planets’ first atmospheres – II. A rapid recycling of atmospheric gas

Ormel

Shi

Kuiper

2015

Monthly Notices of the Royal Astronomical Society

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185

214

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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 extended to three dimensions, employing a spherical grid centred on the planet. Compression of gas is shown to reduce rotational motions. Contrasting the 2D case, no clear boundary demarcates bound atmospheric gas from disc material; instead, we find an open system where gas enters the Bondi sphere at high latitudes and leaves through the midplane regions, or, vice versa, when the disc gas rotates sub-Keplerian. The simulations do not converge to a time-independent solution; instead, the atmosphere is characterized by a time-varying velocity field. Of particular interest is the timescale to replenish the atmosphere by nebular gas, t replenish . It is shown that the replenishment rate, M atm /t replenish , can be understood in terms of a modified Bondi accretion rate, ∼R 2 Bondi ρ gas v Bondi , where v Bondi is set by the Keplerian shear or the magnitude of the sub-Keplerian motion of the gas, whichever is larger. In the inner disk, the atmosphere of embedded protoplanets replenishes on a timescale that is shorter than the Kelvin-Helmholtz contraction (or cooling) timescale. As a result, atmospheric gas can no longer contract and the growth of these atmospheres terminates. Future work must confirm whether these findings continue to apply when the (thermodynamical) idealizations employed in this study are relaxed. But if shown to be broadly applicable, replenishment of atmospheric gas provides a natural explanation for the preponderance of gas-rich but rock-dominant planets like super-Earths and mini-Neptunes.

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Section: Introductionsupporting

confidence: 84%

Hydrodynamics of embedded planets’ first atmospheres – II. A rapid recycling of atmospheric gas

Ormel

Shi

Kuiper

2015

Monthly Notices of the Royal Astronomical Society

Self Cite

185

214

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“…The scale represents the logarithm of the density, in g · cm −3 . grid does describe the accreting planet with a CPD accurately (as discussed in Ormel et al 2015a). Accretion onto the planet occurs not only in the orbital plane from the CPD but also vertically (see e.g.…”

Section: Gas Streamlinesmentioning

confidence: 99%

Detectability of embedded protoplanets from hydrodynamical simulations

Sanchís

Picogna

Ercolano

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-size planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts being transparent to the planet flux in the infrared (IR). Column densities are estimated by means of three-dimensional hydrodynamical models, performed for several planet masses. Expected magnitudes are obtained by using typical extinction properties of the disc material and evolutionary models of giant planets. For the simulated cases located at 5.2 AU in a disc with local unperturbed surface density of 127 g · cm −2 , a 1 M J planet is highly extincted in J-, H-and Kbands, with predicted absolute magnitudes ≥ 50 mag. In L-and M-bands extinction decreases, with planet magnitudes between 25 and 35 mag. In the N-band, due to the silicate feature on the dust opacities, the expected magnitude increases to ∼ 40 mag. For a 2 M J planet, the magnitudes in J-, H-and K-bands are above 22 mag, while for L-, M-and N-bands the planet magnitudes are between 15 and 20 mag. For the 5 M J planet, extinction does not play a role in any IR band, due to its ability to open deep gaps. Contrast curves are derived for the transition discs in CQ Tau, PDS 70, HL Tau, TW Hya and HD 163296. Planet mass upper-limits are estimated for the known gaps in the last two systems.

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“…Only Jupiter-mass planets reveal a hint of a disk-like structure which shows strongly sub-Keplerian rotation. Possibly, this is related to a more 2D-like mass flow around larger mass planets (Ormel et al 2015a).…”

Section: Rotation In the Envelope And Implications For Satellite Formmentioning

confidence: 99%

Quasi-static contraction during runaway gas accretion onto giant planets

Lambrechts

Lega

Nelson

et al. 2019

A&A

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Gas-giant planets, like Jupiter and Saturn, acquire massive gaseous envelopes during the approximately 3 Myr-long lifetimes of protoplanetary discs. In the core accretion scenario, the formation of a solid core of around 10 Earth masses triggers a phase of rapid gas accretion. Previous 3D grid-based hydrodynamical simulations found runaway gas accretion rates corresponding to approximately 10 to 100 Jupiter masses per Myr. Such high accretion rates would result in all planets with larger-than-10-Earth-mass cores forming Jupiter-like planets, in clear contrast to the ice giants in the Solar System and the observed exoplanet population. In this work, we use 3D hydrodynamical simulations, that include radiative transfer, to model the growth of the envelope on planets with different masses. We find that gas flows rapidly through the outer part of the envelope, but this flow does not drive accretion. Instead, gas accretion is the result of quasi-static contraction of the inner envelope, which can be orders of magnitude smaller than the mass flow through the outer atmosphere. For planets smaller than Saturn, we measure moderate gas accretion rates that are below 1 Jupiter mass per Myr. Higher mass planets, however, accrete up to 10 times faster and do not reveal a self-driven mechanism that can halt gas accretion. Therefore, the reason for the final masses of Saturn and Jupiter remains difficult to understand, unless their completion coincided with the dissipation of the Solar Nebula.

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Hydrodynamics of embedded planets’ first atmospheres – I. A centrifugal growth barrier for 2D flows

Cited by 80 publications

References 57 publications

Hydrodynamics of embedded planets’ first atmospheres – II. A rapid recycling of atmospheric gas

Hydrodynamics of embedded planets’ first atmospheres – II. A rapid recycling of atmospheric gas

Detectability of embedded protoplanets from hydrodynamical simulations

Quasi-static contraction during runaway gas accretion onto giant planets

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