Comets and Asteroids

Comet 81P/Wild 2: A Record of the Solar System’s Wild Youth

By Keith Cowing
Status Report
December 2, 2023
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Comet 81P/Wild 2: A Record of the Solar System’s Wild Youth
Carbon to silicon atom ratios in comets and other objects, from Woodward et al. (2021). — astro-ph.EP

NASA’s Stardust mission returned rocky material from the coma of comet 81P/Wild 2 (pronounced “Vilt 2”) to Earth for laboratory study on January 15, 2006. Comet Wild 2 contains volatile ices and likely accreted beyond the orbit of Neptune.

It was expected that the Wild 2 samples would contain abundant primordial molecular cloud material–interstellar and circumstellar grains. Instead, the interstellar component of Wild 2 was found to be very minor, and nearly all of the returned particles formed in broad and diverse regions of the solar nebula.

While some characteristics of the Wild 2 material are similar to primitive chondrites, its compositional diversity testifies to a very different origin and evolution history than asteroids. Comet Wild 2 does not exist on a continuum with known asteroids. Collisional debris from asteroids is mostly absent in Wild 2, and it likely accreted dust from the outer and inner Solar System (across the putative gap created by a forming Jupiter) before dispersal of the solar nebula. Comets are a diverse set of bodies, and Wild 2 may represent a type of comet that accreted a high fraction of dust processed in the young Solar System.

Ryan C. Ogliore

Comments: 60 pages, 9 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2311.18119 [astro-ph.EP] (or arXiv:2311.18119v1 [astro-ph.EP] for this version)
Submission history
From: Ryan Ogliore
[v1] Wed, 29 Nov 2023 22:14:12 UTC (8,591 KB)
Astrobiology, astrochemistry,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻