Protoplanetary Cores Drove Chondrule Formation
Chondrules are small spherical objects that formed at high temperatures early in the history of the Solar System. The key compositional characteristics of chondrules may be well explained by high gas pressures in their formation environment (Galy et al. 2000; Alexander et al. 2008).
However, such high gas pressures are widely considered astrophysically unreasonable (Ebel et al. 2023). Here, we propose that chondrules were formed via the processing of dust grains in the dust-rich envelopes of planetary embryos, before getting ejected via convective diffusion.
We show that this scenario can explain many salient constraints on chondrule formation, including formation locations; mass and timescale of chondrule production; repeat chondrule heating events; heating timescales; and, most crucially, high prevailing gas pressures. Our work suggests that high gas pressures may indeed have prevailed during the formation of chondrules, reconciling previous analytical observations, experimental evidence, and theory.
We suggest that chondrules are mostly the products rather than the precursors of planetary embryo formation – a result which would have important implications for our understanding of the early history of the Solar System.
Schematic view of chondrule formation scenarios. A) Two end-member views are shown. On the left, the branch of scenarios is depicted in which chondrules are generally products of planet formation. On the right, the branch of scenarios is depicted in which chondrules are generally precursors to planet formation, i.e., forming earlier than planetary embryos and acting as seed materials for their eventual growth. B) Detailed schematic view of our proposed embryo-first scenario for chondrule formation. We propose that planetary embryos produces chondrules during interactions with dust particles, which enter the atmospheric envelope, become heated, and some fraction of which is then ejected via convective diffusion through the envelope. This mechanism allows for the possibility of some small fraction of this dust following a path involving multiple heating cycles. — astro-ph.EP
Mohamad Ali-Dib, Craig Walton
Comments: 8 pages, 5 figures, resubmitted to MNRAS after revision
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2503.16325 [astro-ph.EP] (or arXiv:2503.16325v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2503.16325
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Submission history
From: Mohamad Ali-Dib
[v1] Thu, 20 Mar 2025 16:45:24 UTC (1,617 KB)
https://arxiv.org/abs/2503.16325
Astrobiology, Astrochemistry, Astrogeology,
