Formation of terrestrial planet cores inside giant planet embryos

Abstract

Giant planet embryos are believed to be spawned by gravitational instability in massive extended (R ~ 100 AU) protostellar discs. In a recent paper we have shown that dust can sediment inside the embryos, as argued earlier by Boss (1998) in a slightly different model. Here we study numerically the next stage of this process -- the formation of a solid core. If conditions are conducive to solid core formation, the centre of the gas cloud goes through the following sequence of phases: (i) becomes grain (and metal) rich; (ii) forms a terrestrial mass solid core via a rapid collapse driven by self-gravity of the grains; (iii) starts to accrete a gaseous atmosphere when the solid core reaches mass of a few to 10 Earth masses. This sequence of events may build either terrestrial planet cores or metal rich giant planets inside the larger gas reservoir of the giant planet embryo. In a companion Letter we argue that tidal and irradiation effects from the parent star should disrupt the outer metal poor layers of the embryo, releasing nearly "ready to use" planets. We propose this as an alternative way to build planets.

20 pages, submitted to MNRAS, referred to as "paper II" in series

References in corpus (12)

• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• Starbursts near supermassive black holes: young stars in the Galactic Center, and gravitational waves in LISA band
• The physical properties of extrasolar planets
• Dust settling in local simulations of turbulent protoplanetary disks
• Formation Process of the Circumstellar Disk: Long-term Simulations in the Main Accretion Phase of Star Formation
• Can giant planets form by gravitational fragmentation of discs?
• Grain sedimentation inside giant planet embryos
• Emergence of Protoplanetary Disks and Successive Formation of Gaseous Planets by Gravitational Instability
• Massive planet migration: Theoretical predictions and comparison with observations
• Core Formation in Giant Gaseous Protoplanets
• On The Possibility of Enrichment and Differentiation in Gas Giants During Birth by Disk Instability
• Grain Sedimentation in a Giant Gaseous Protoplanet

Cited by in corpus (34)

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• The Dynamical Fate of Self-Gravitating Disc Fragments After Tidal Downsizing
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• The Tidal Downsizing hypothesis for planet formation and the composition of Solar System comets
• An alternative origin for debris rings of planetesimals
• Core-assisted gas capture instability: a new mode of giant planet formation by gravitationally unstable discs
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• TW Hya: an old protoplanetary disc revived by its planet
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• Characterizing fragmentation and sub-Jovian clump properties in magnetized young protoplanetary disks
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• Hydrogen-loosing planets in transition discs around young protostars
• Planets, debris and their host metallicity correlations