Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tidal Downsizing model. I. Numerical methods: saving giant planets from
  tidal disruptions   Tidal Downsizing (TD) is a recently developed planet formation theory that
supplements the classical Gravitational disc Instability (GI) model with planet
migration inward and tidal disruptions of GI fragments in the inner regions of
the disc. Numerical methods for a detailed population synthesis of TD planets
are presented here. As an example application, the conditions under which GI
fragments collapse faster than they migrate into the inner $a\sim$ few AU disc
are considered. It is found that most gas fragments are tidally or thermally
disrupted unless (a) their opacity is $\sim 3$ orders of magnitude less than
the interstellar dust opacity at metallicities typical of the observed giant
planets, or (b) the opacity is high but the fragments accrete large dust grains
(pebbles) from the disc. Case (a) models produce very low mass solid cores
($M_{\rm core} < 0.1$ Earth masses) and follow a negative correlation of giant
planet frequency with host star metallicity. In contrast, case (b) models
produce massive solid cores, correlate positively with host metallicity and
explain naturally while giant gas planets are over-abundant in metals.

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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys