Two distinct populations of dark comets delineated by orbits and sizes

• 成果类型: Article
• 署名作者: Seligman, Darryl Z.; Farnocchia, Davide; Micheli, Marco; Hainaut, Olivier R.; Hsieh, Henry H.; Feinstein, Adina D.; Chesley, Steven R.; Taylor, Aster G.; Masiero, Joseph; Meech, Karen J.
• 署名单位: Michigan State University; Cornell University; Cornell University; California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); European Space Agency; European Southern Observatory; University of Colorado System; University of Colorado Boulder; University of Michigan System; University of Michigan; California Institute of Technology; University of Hawaii System
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11537
• DOI: 10.1073/pnas.2406424121
• 发表日期: 2024-12-17
• 关键词: hayabusa2 extended mission; navigation camera onc; asteroid 162173 ryugu; radiation pressure; inflight calibration; earth; onboard; search; origin; FAMILY

摘要

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 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 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 similar to 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 different different 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.