Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effect of late giant collisions on the atmospheres of protoplanets
  and the formation of cold sub-Saturns   We investigate the origins of cold sub-Saturns (CSS), an exoplanetary
population inferred from microlensing surveys. If confirmed, these planets
would rebut a theorised gap in planets' mass distribution between those of
Neptune and Jupiter caused by the rapid runaway accretion of super-critical
cores. In an attempt to resolve this theoretical-observational disparity, we
examine the outcomes of giant collisions between sub-critical protoplanets. Due
to the secular interaction among protoplanets, these events may occur in
rapidly depleting discs. We show that impactors ~ 5% the mass of near-runaway
envelopes around massive cores can efficiently remove these envelopes entirely
via a thermally-driven super-Eddington wind emanating from the core itself, in
contrast with the stellar Parker winds usually considered. After a brief
cooling phase, the merged cores resume accretion. But, the evolution timescale
of transitional discs is too brief for the cores to acquire sufficiently
massive envelopes to undergo runaway accretion despite their large combined
masses. Consequently, these events lead to the emergence of CSS without their
transformation into gas giants. We show that these results are robust for a
wide range of disc densities, grain opacities and silicate abundance in the
envelope. Our fiducial case reproduces CSS with heavy (>= 30 M_Earth) cores and
less massive (a few M_Earth) sub-critical envelopes. We also investigate the
other limiting cases, where continuous mergers of comparable-mass cores yield
CSS with wider ranges of core-to-envelope mass ratios and envelope opacities.
Our results indicate that it is possible for CSS and Uranus and Neptune to
emerge within the framework of well studied processes and they may be more
common than previously postulated.

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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
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The categories of this paper are: stat
20
The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin