Impact of Radiogenic Heating on the Formation Conditions of Comet 67P/Churyumov–Gerasimenko

Journal Article · Mon Apr 10 00:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA6839· OSTI ID:22654500

Mousis, O.; Drouard, A.; Vernazza, P.; Le Deun, T. ^[1]; Lunine, J. I. ^[2]; Monnereau, M.; Rème, H. ^[3]; Maggiolo, R.; Cessateur, G.; De Keyser, J.; Gasc, S. ^[4]; Altwegg, K.; Balsiger, H.; Rubin, M.; Tzou, C. -Y. ^[5]; Berthelier, J. -J. ^[6]; Fuselier, S. A. ^[7]; Korth, A.; Mall, U. ^[8]; others, and

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1. Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)
2. Department of Astronomy and Carl Sagan Institute, Space Sciences Building Cornell University, Ithaca, NY 14853 (United States)
3. Université de Toulouse, UPS-OMP-CNRS, IRAP, Toulouse (France)
4. Royal Belgian Institute for Space Aeronomy, BIRA-IASB, Ringlaan 3, B-1180 Brussels (Belgium)
5. Physikalisches Institut, University of Bern, Sidlerstr. 5, CH-3012 Bern (Switzerland)
6. LATMOS/IPSL-CNRS-UPMC-UVSQ, 4 Avenue de Neptune F-94100, Saint-Maur (France)
7. Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228 (United States)
8. Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

Because of the high fraction of refractory material present in comets, the heat produced by the radiogenic decay of elements such as aluminum and iron can be high enough to induce the loss of ultravolatile species such as nitrogen, argon, or carbon monoxide during their accretion phase in the protosolar nebula (PSN). Here, we investigate how heat generated by the radioactive decay of {sup 26}Al and {sup 60}Fe influences the formation of comet 67P/Churyumov–Gerasimenko, as a function of its accretion time and the size of its parent body. We use an existing thermal evolution model that includes various phase transitions, heat transfer in the ice-dust matrix, and gas diffusion throughout the porous material, based on thermodynamic parameters derived from Rosetta observations. Two possibilities are considered: either, to account for its bilobate shape, 67P/Churyumov–Gerasimenko was assembled from two primordial ∼2 km sized planetesimals, or it resulted from the disruption of a larger parent body with a size corresponding to that of comet Hale–Bopp (∼70 km). To fully preserve its volatile content, we find that either 67P/Churyumov–Gerasimenko’s formation was delayed between ∼2.2 and 7.7 Myr after that of Ca–Al-rich Inclusions in the PSN or the comet’s accretion phase took place over the entire time interval, depending on the primordial size of its parent body and the composition of the icy material considered. Our calculations suggest that the formation of 67P/Churyumov–Gerasimenko is consistent with both its accretion from primordial building blocks formed in the nebula or from debris issued from the disruption of a Hale–Bopp-like body.

• OSTI ID: 22654500
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 839; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
79 ASTRONOMY AND ASTROPHYSICS
ALUMINIUM
ARGON
CARBON MONOXIDE
COMETS
COMPUTERIZED SIMULATION
IRON
LOSSES
NITROGEN
PLANET-SYSTEM ACCRETION
SOLAR NEBULA
SPACE
SPACE VEHICLES