Comets and Asteroids

Two Distinct Populations of Dark Comets Delineated by Orbits and Sizes

By Keith Cowing

Status Report

astro-ph.EP

December 14, 2024

Filed under 1998 FR11, 2001 ME1, 2003 RM, astro-ph.EP, astrochemistry, astrogeology, astronomy, Comet, icy world, near-Earth objects, organic chemistry, Planetesimal, Spectroscopy

Two Distinct Populations of Dark Comets Delineated by Orbits and Sizes — The orbits of the fourteen currently known dark comets, Jupiter, and the Earth. One orbital period is shown for each object starting on the vernal equinox in 2023 March, and the points represent the corresponding initial positions of the Earth and of Jupiter. The left and right panels highlight the orbits of the outer and inner dark comets respectively. Orbits of the newly discovered dark comets are labeled with italicized font, and the orbits of previously reported objects are labeled in roman font. –PNAS

Small bodies are capable of delivering essential prerequisites for the development of life, such as volatiles and organics, to the terrestrial planets. For example, empirical evidence suggests that water was delivered to the Earth by hydrated planetesimals from distant regions of the Solar System.

Recently, several morphologically inactive near-Earth objects (NEOs) were reported to experience significant nongravitational accelerations inconsistent with radiation-based effects, and possibly explained by volatile-driven outgassing.

However, these “dark comets” display no evidence of comae in archival images, which are the defining feature of cometary activity. Here we report detections of nongravitational accelerations on seven additional objects previously classified as inactive (doubling the population) that could also be explainable by asymmetric mass loss.

A detailed search of archival survey and targeted data rendered no detection of dust activity in any of these objects in individual or stacked images. We calculate dust production limits of ∼10, 0.1, and 0.1 kg s−1 for 1998 FR11, 2001 ME1, and 2003 RM with these data, indicating little or no dust surrounding the objects during the observations.

This set of dark comets reveals the delineation between two distinct populations: larger, “outer” dark comets on eccentric orbits that are end members of a continuum in activity level of comets, and smaller, “inner” dark comets on near-circular orbits that could signify a new population.

These objects may trace various stages in the life cycle of a previously undetected, but potentially numerous, volatile-rich population that may have provided essential material to the Earth.

Darryl Z. Seligman, Davide Farnocchia, Marco Micheli, Olivier R. Hainaut, Henry H. Hsieh, Adina D. Feinstein, Steven R. Chesley, Aster G. Taylor, Joseph Masiero, Karen J. Meech

Comments: 12 pages, 11 figures, Author’s version of Proc. Natl. Acad. Sci. Vol. 121 No. 51 published at this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2412.07603 [astro-ph.EP] (or arXiv:2412.07603v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2412.07603
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Journal reference: Proc. Natl. Acad. Sci., 121, 2024
Related DOI:
https://doi.org/10.1073/pnas.2406424121
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Submission history
From: Darryl Seligman
[v1] Tue, 10 Dec 2024 15:43:53 UTC (1,008 KB)
https://arxiv.org/abs/2412.07603
Astrobiology

Keith Cowing

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) 🖖🏻

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