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Oscillatory migration of accreting protoplanets driven by a 3D distortion of the gas flow

Chrenko, Ondřej and Lambrechts, Michiel LU (2019) In Astronomy and Astrophysics 626.
Abstract

Context. The dynamics of a low-mass protoplanet accreting solids is influenced by the heating torque, which was found to suppress inward migration in protoplanetary disks with constant opacities. Aims. We investigate the differences in the heating torque between disks with constant and temperature-dependent opacities. Methods. Interactions of a super-Earth-sized protoplanet with the gas disk are explored using 3D radiation hydrodynamic simulations. Results. Accretion heating of the protoplanet creates a hot underdense region in the surrounding gas, leading to misalignment of the local density and pressure gradients. As a result, the 3D gas flow is perturbed and some of the streamlines form a retrograde spiral rising above the... (More)

Context. The dynamics of a low-mass protoplanet accreting solids is influenced by the heating torque, which was found to suppress inward migration in protoplanetary disks with constant opacities. Aims. We investigate the differences in the heating torque between disks with constant and temperature-dependent opacities. Methods. Interactions of a super-Earth-sized protoplanet with the gas disk are explored using 3D radiation hydrodynamic simulations. Results. Accretion heating of the protoplanet creates a hot underdense region in the surrounding gas, leading to misalignment of the local density and pressure gradients. As a result, the 3D gas flow is perturbed and some of the streamlines form a retrograde spiral rising above the protoplanet. In the constant-opacity disk, the perturbed flow reaches a steady state and the underdense gas responsible for the heating torque remains distributed in accordance with previous studies. If the opacity is non-uniform, however, the differences in the disk structure can lead to more vigorous streamline distortion and eventually to a flow instability. The underdense gas develops a one-sided asymmetry which circulates around the protoplanet in a retrograde fashion. The heating torque thus strongly oscillates in time and does not on average counteract inward migration. Conclusions. The torque variations make the radial drift of the protoplanet oscillatory, consisting of short intervals of alternating rapid inward and outward migration. We speculate that transitions between the positive and oscillatory heating torque may occur in specific disk regions susceptible to vertical convection, resulting in the convergent migration of multiple planetary embryos.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hydrodynamics, Planet-disk interactions, Planets and satellites: formation, Protoplanetary disks
in
Astronomy and Astrophysics
volume
626
publisher
EDP Sciences
external identifiers
  • scopus:85068331049
ISSN
0004-6361
DOI
10.1051/0004-6361/201935334
language
English
LU publication?
yes
id
3259fedc-2378-4a16-98c9-521811f1b8f6
date added to LUP
2019-07-12 10:34:56
date last changed
2019-08-06 03:24:18
@article{3259fedc-2378-4a16-98c9-521811f1b8f6,
  abstract     = {<p>Context. The dynamics of a low-mass protoplanet accreting solids is influenced by the heating torque, which was found to suppress inward migration in protoplanetary disks with constant opacities. Aims. We investigate the differences in the heating torque between disks with constant and temperature-dependent opacities. Methods. Interactions of a super-Earth-sized protoplanet with the gas disk are explored using 3D radiation hydrodynamic simulations. Results. Accretion heating of the protoplanet creates a hot underdense region in the surrounding gas, leading to misalignment of the local density and pressure gradients. As a result, the 3D gas flow is perturbed and some of the streamlines form a retrograde spiral rising above the protoplanet. In the constant-opacity disk, the perturbed flow reaches a steady state and the underdense gas responsible for the heating torque remains distributed in accordance with previous studies. If the opacity is non-uniform, however, the differences in the disk structure can lead to more vigorous streamline distortion and eventually to a flow instability. The underdense gas develops a one-sided asymmetry which circulates around the protoplanet in a retrograde fashion. The heating torque thus strongly oscillates in time and does not on average counteract inward migration. Conclusions. The torque variations make the radial drift of the protoplanet oscillatory, consisting of short intervals of alternating rapid inward and outward migration. We speculate that transitions between the positive and oscillatory heating torque may occur in specific disk regions susceptible to vertical convection, resulting in the convergent migration of multiple planetary embryos.</p>},
  articleno    = {A109},
  author       = {Chrenko, Ondřej and Lambrechts, Michiel},
  issn         = {0004-6361},
  keyword      = {Hydrodynamics,Planet-disk interactions,Planets and satellites: formation,Protoplanetary disks},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {Oscillatory migration of accreting protoplanets driven by a 3D distortion of the gas flow},
  url          = {http://dx.doi.org/10.1051/0004-6361/201935334},
  volume       = {626},
  year         = {2019},
}