When comets get old: A synthesis of comet and meteor observations of the low activity comet 209P/LINEAR

• Published in: Icarus (New York, N.Y. 1962) Vol. 264; pp. 48 - 61
• Main Authors: Ye (叶泉志), Quan-Zhi, Hui (许文韬), Man-To, Brown, Peter G., Campbell-Brown, Margaret D., Pokorný, Petr, Wiegert, Paul A., Gao (高兴), Xing
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.01.2016
• Subjects: Asteroids; Comet nuclei; Comets; Comets, dust; Comets, dynamics; Comets, nucleus; Computer simulation; Dust; Meteors; Near-Earth objects; Orbits; Synthesis; Comets, dust; Comets, dynamics; Comets, nucleus; Meteors; Near-Earth objects
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2015.09.003

•We present comet and meteor observations of weakly active Comet 209P/LINEAR.•The coma is dominated by large dust grains with ejection speed 1/10 of normal comets.•The dust production is found to be very low over the past few hundred orbits.•209P/LINEAR may have resided in a stable near-Earth orbit for ∼104yr.•209P/LINEAR may be an aging comet quietly exhausting its near surface volatiles. It is speculated that some weakly active comets may be transitional objects between active and dormant comets. These objects are at a unique stage of the evolution of cometary nuclei, as they are still identifiable as active comets, in contrast to inactive comets that are observationally indistinguishable from low albedo asteroids. In this paper, we present a synthesis of comet and meteor observations of Jupiter-family Comet 209P/LINEAR, one of the most weakly active comets recorded to-date. Images taken by the Xingming 0.35-m telescope and the Gemini Flamingo-2 camera are modeled by a Monte Carlo dust model, which yields a low dust ejection speed (1/10 of that of moderately active comets), dominance of large dust grains, and a low dust production of 0.4kgs-1 at 19d after the 2014 perihelion passage. We also find a reddish nucleus of 209P/LINEAR that is similar to D-type asteroids and most Trojan asteroids. Meteor observations with the Canadian Meteor Orbit Radar (CMOR), coupled with meteoroid stream modeling, suggest a low dust production of the parent over the past few hundred orbits, although there are hints of a some temporary increase in activity in the 18th century. Dynamical simulations indicate 209P/LINEAR may have resided in a stable near-Earth orbit for ∼104yr, which is significantly longer than typical JFCs. All these lines of evidence imply that 209P/LINEAR as an aging comet quietly exhausting its remaining near surface volatiles. We also compare 209P/LINEAR to other low activity comets, where evidence for a diversity of the origin of low activity is seen.