Constraining protoplanetary disks with exoplanetary dynamics: Kepler-419 as an example. (arXiv:2009.06448v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ali_Dib_M/0/1/0/all/0/1">Mohamad Ali-Dib</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petrovich_C/0/1/0/all/0/1">Cristobal Petrovich</a>
We investigate the origins of Kepler-419, a peculiar system hosting two
nearly coplanar and highly eccentric gas giants with apsidal orientations
librating around anti-alignment, and use this system to place constraints on
the properties of their birth protoplanetary disk. We follow the proposal by
Petrovich, Wu, & Ali-Dib (2019) that these planets have been placed on these
orbits as a natural result of the precessional effects of a dissipating massive
disk and extend it by using direct N-body simulations and models for the
evolution of the gas disks, including photoevaporation. Based on a parameter
space exploration, we find that in order to reproduce the system the initial
disk mass had to be at least 95 M_Jup and dissipate on a timescale of at least
10^4 yr. This mass is consistent with the upper end of the observed disk masses
distribution, and the dissipation timescale is consistent with photoevaporation
models. We study the properties of such disks using simplified 1D thin disk
models and show that they are gravitationally stable, indicating that the two
planets must have formed via core accretion and thus prone to disk migration.
We hence finally investigate the sensitivity of this mechanism to the outer
planet’s semi major axis, and find that the nearby 7:1, 8:1, and 9:1
mean-motion resonances can completely quench this mechanism, while even higher
order resonances can also significantly affect the system. Assuming the two
planets avoid these high order resonances and/or close encounters, the dynamics
seems to be rather insensitive to planet c semi major axis, and thus orbital
migration driven by the disk.
We investigate the origins of Kepler-419, a peculiar system hosting two
nearly coplanar and highly eccentric gas giants with apsidal orientations
librating around anti-alignment, and use this system to place constraints on
the properties of their birth protoplanetary disk. We follow the proposal by
Petrovich, Wu, & Ali-Dib (2019) that these planets have been placed on these
orbits as a natural result of the precessional effects of a dissipating massive
disk and extend it by using direct N-body simulations and models for the
evolution of the gas disks, including photoevaporation. Based on a parameter
space exploration, we find that in order to reproduce the system the initial
disk mass had to be at least 95 M_Jup and dissipate on a timescale of at least
10^4 yr. This mass is consistent with the upper end of the observed disk masses
distribution, and the dissipation timescale is consistent with photoevaporation
models. We study the properties of such disks using simplified 1D thin disk
models and show that they are gravitationally stable, indicating that the two
planets must have formed via core accretion and thus prone to disk migration.
We hence finally investigate the sensitivity of this mechanism to the outer
planet’s semi major axis, and find that the nearby 7:1, 8:1, and 9:1
mean-motion resonances can completely quench this mechanism, while even higher
order resonances can also significantly affect the system. Assuming the two
planets avoid these high order resonances and/or close encounters, the dynamics
seems to be rather insensitive to planet c semi major axis, and thus orbital
migration driven by the disk.
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