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Metal loading of giant gas planets

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journal contribution
posted on 23.04.2015, 14:49 by Sergei Nayakshin
One of many challenges in forming giant gas planets via gravitational disc instability model is an inefficient radiative cooling of the pre-collapse fragments. Since fragment contraction times are as long as 105–107 yr, the fragments may be tidally destroyed sooner than they contract onto gas giant planets. Here, we explore the role of ‘pebble accretion’ the pre-collapse giant planets and find an unexpected result. Despite larger dust opacity at higher metallicities, addition of metals actually accelerates – rather than slows down – collapse of high-opacity, relatively low mass giant gas planets (Mp ≲ a few Jupiter masses). A simple analytical theory that explains this result exactly in idealized simplified cases is presented. The theory shows that planets with the central temperature in the range of 1000 ≲ Tc ≲ 2000 K are especially sensitive to pebble accretion: addition of just ∼5 to 10 per cent of metals by weight is sufficient to cause their collapse. These results show that dust grain physics and dynamics are essential for an accurate modelling of self-gravitating disc fragments and their near environments in the outer massive and cold protoplanetary discs.

Funding

Theoretical astrophysics research at the University of Leicester is supported by an STFC rolling grant.

History

Citation

Monthly Notices of the Royal Astronomical Society, 2015, 446 (1), pp. 459-469 (11)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press (OUP), Royal Astronomical Society

issn

0035-8711

eissn

1365-2966

Copyright date

2014

Available date

23/04/2015

Publisher version

http://mnras.oxfordjournals.org/content/446/1/459

Language

en