Disintegration of Comet C/2012 S1 (ISON) Shortly Before Perihelion: Evidence from Independent Data Sets
Abstract
As an Oort Cloud object with a record small perihelion distance of 2.7 Rsun and discovered more than a year before its encounter with the Sun, comet C/2012 S1 is a subject of considerable scientific interest. Its activity along the orbit's inbound leg evolved through a series of cycles. Two remarkable events preserved in SOHO's and/or STEREO's near-perihelion images of its tail were an early massive production of gravel at heliocentric distances of up to ~100 AU, evidently by the annealing of amorphous water ice on and near the nucleus' surface; and, about a week before perihelion, a rapid series of powerful explosions, from the comet's interior, of water with dust at extremely high rates, causing precipitous fragmentation of the nucleus, shattering it into a vast number of sublimating boulders, and ending up, a few days later, with a major, sudden drop in gas emission. The disintegration of the comet was completed by about 3.5 hours before perihelion, at a heliocentric distance of 5.2 Rsun, when C/2012 S1 ceased to exist as an active comet. The orbital motion in this period of time was subjected to progressively increasing outgassing-driven perturbations. A comprehensive orbital analysis results in successfully fitting the comet's observed motion from 2011 to ~7 hours before perihelion.
- Publication:
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arXiv e-prints
- Pub Date:
- April 2014
- DOI:
- 10.48550/arXiv.1404.5968
- arXiv:
- arXiv:1404.5968
- Bibcode:
- 2014arXiv1404.5968S
- Keywords:
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- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 49 pages, 25 figures, 17 tables