Late giant collisions between sub-critical protoplanets could produce cold sub-Saturns without turning them into gas giants, according to the paper's models.

The paper

The paper's details are OpenAlex's; the citation count is OpenAlex's, 21 Oct 2026. The line on the paper is machine-written, as noted under Why it matters.

Why it matters

Written by Claude (claude-sonnet-5-5) on 21 Oct 2026 from the paper's abstract (as arXiv publishes it) and its OpenAlex record. Machine-written context to help a reader: it is not evidence, it moves no number, and it may be wrong. The quoted sentence is the claim; where it stands is computed from the record. If it misreads the paper, tell the stewards.

The story so far

1. 1

   What the authors did

   The authors modelled giant collisions between sub-critical protoplanets and how their gas envelopes respond, then followed the merged cores' regrowth over the short lifetime of transitional discs. They tested a range of disc densities, grain opacities and silicate abundances.

   Machine-written from the paper's abstract, as noted under Why it matters.

2. 2

   What they found

   • Impactors about 5% of the mass of a near-runaway envelope can remove that envelope entirely through a thermally driven super-Eddington wind from the core.
   • After a brief cooling phase the merged cores resume accretion, but transitional discs evolve too quickly for them to gain envelopes massive enough for runaway accretion.
   • The fiducial case gives cold sub-Saturns with heavy cores (at least 30 Earth masses) and small envelopes of a few Earth masses, and continuous mergers of comparable-mass cores give wider ranges of core-to-envelope mass ratios.

   Machine-written from the paper's abstract, as noted under Why it matters.

3. 3

   What has been checked on Ecdysis

   Exuvia registered the claim on 21 October 2026, with a test written from the paper. No check has been filed yet.

What would check it

How far it has been checked

1. 1
   The object itself, checked againverification · not yet

   Not yet: re-run the paper's analysis on its own data, where the authors have published it.

2. 2
   New instances of the constructionreproduction · not yet

   Not yet: the same construction run afresh.

3. 3
   The designrobustness tests and arguments · not yet

   Nothing yet: change the method or the data and see whether it holds (a robustness test), or argue that the method does not test what the claim says.

How sure is the record?

Share this finding

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Click a post's text to select all of it. Both posts give the claim's standing on the record, and the longer one says what the checks show and what they do not; the wording changes when the record does. The longer post quotes the paper first, then gives the machine-written headline, marked as such; edit it as you like. To cite the claim, see Cite this claim.

What would prove it wrong

Refuted if for all relevant disc densities, grain opacities and silicate abundances every simulated collision between sub‑critical protoplanets in a rapidly depleting disc either results in complete loss of the planet or leads to runaway gas accretion that produces a gas giant rather than a cold sub‑Saturn.

The test as Exuvia registered it on 21 Oct 2026, written from the paper's words.

The wider literature

Other claims from the same paper

• uncheckedImpactors about 5% of the mass of a near-runaway envelope can strip it entirely via a thermally driven wind from the core, per the paper's models.“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…”
• uncheckedAfter merging, the cores resume gas accretion, but transitional discs fade too quickly for them to build envelopes massive enough for runaway 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.”

Headlines are machine-written from the paper's abstract, or from the quote and the paper's title where no abstract is open; each claim's own words are quoted beneath its headline.