Rapid inward migration of planets formed by gravitational instability

By C. Baruteau, F. Meru, S. Paardekooper. 2011

133 citations recorded by the source corpus.

The observation of massive exoplanets at large separation (10 au) from their host star, like in the HR 8799 system, challenges theories of planet formation. A possible formation mechanism involves the fragmentation of massive self-gravitating discs into clumps. While the conditions for fragmentation have been extensively studied, little is known of the subsequent evolution of these giant planet embryos, in particular their expected orbital migration. Assuming a single planet has formed by fragmentation, we investigate its interaction with the gravitoturbulent disc it is embedded in. 2D hydrodynamical simulations are used with a simple prescription for the disc cooling. A steady gravitoturbulent disc is first set up, after which simulations are restarted including a planet with a range of masses approximately equal to the clump’s initial mass expected in fragmenting discs. Planets rapidly migrate inwards, despite the stochastic kicks due to the turbulent density fluctuations. We show that the migration time-scale is essentially that of type I migration, with the planets having no time to open a gap. In discs with aspect ratio ∼0.1 at their forming location, planets with a mass comparable to or larger than Jupiter’s can migrate in as short as 10 4 years, that is about 10 orbits at 100 au. Massive planets formed at large separation from their star by gravitational instability are thus unlikely to stay in place, and should rapidly migrate towards the inner parts of protoplanetary discs, regardless of the planet mass.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a361468dec0d2d0d6700076eb1a60b2d6d973810

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Citations in the corpus

Gravitational Instabilities in Circumstellar Disks (2016, background): “Baruteau et al. (2011) have confirmed in 2D simulations that the migration of such objects in gravitationally unstable disks is quite rapid, and that the gap opening criteria is accurate even in such disks.”
DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504 (2013, background): “However, the planet would have to escape the very rapid inward migration expected in a turbulent disk (Baruteau et al. 2011).”
CHALLENGES IN FORMING PLANETS BY GRAVITATIONAL INSTABILITY: DISK IRRADIATION AND CLUMP MIGRATION, ACCRETION, AND TIDAL DESTRUCTION (2011, result): “This is consistent with recent papers on the same subject by Baruteau et al. (2011) and Michael et al. (2011).”
Planet-Disk Interaction and Orbital Evolution (2012, background): “The results for power-law disk models from Baruteau et al. (2011) were compared with equivalent viscous laminar disk simulations and with analytic torque estimates, and were found to be in good agreement, demonstrating further the existence of unsaturated corotation torques in turbulent disks.”
JUPITER MODELS WITH IMPROVED AB INITIO HYDROGEN EQUATION OF STATE (H-REOS.2) (2011, background): “…Leconte et al. 2009), tidally disrupted (WASP-12b; Li et al. 2010), that are thought to have formed by gravitational instability (HR 8799be; Baruteau et al. 2011), or that even allow to study non-equilibrium chemistry in irradiated atmospheres (HD 189733b; Fortney et al. 2010), have drawn…”
FORMATION OF MASSIVE PRIMORDIAL STARS: INTERMITTENT UV FEEDBACK WITH EPISODIC MASS ACCRETION (2015, background): “The rapid inward migration of the fragments in gravitationally unstable disks is also commonly seen in simulations of present-day star and planet formation (e.g., Vorobyov & Basu 2006; Baruteau et al. 2011; Machida et al. 2011; Zhu et al. 2012).”
Possible planet-forming regions on submillimetre images (2011, background): “Dodson-Robinson et al. found that the only possible scenario to form stable wide-orbit planets is the gravitational instability, but planets formed this way were recently shown (by Baruteau et al. 2011) to migrate quite rapidly inwards – puts in question its feasibility.”