DYNAMICS OF LARGE FRAGMENTS IN THE TAIL OF ACTIVE ASTEROID P/2010 A2
- Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany)
- Department of Earth and Space Sciences and Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095-1567 (United States)
- Johns Hopkins University Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States)
We examine the motions of large fragments at the head of the dust tail of the active asteroid P/2010 A2. In previous work, we showed that these fragments were ejected from the primary nucleus in early 2009, either following a hypervelocity impact or by rotationally induced breakup. Here, we follow their positions through a series of Hubble Space Telescope images taken during the first half of 2010. The orbital evolution of each fragment allows us to constrain its velocity relative to the main nucleus after leaving its sphere of gravitational influence. We find that the fragments constituting a prominent X-shaped tail feature were emitted in a direction opposite to the motion of the asteroid and toward the south of its orbital plane. Derived emission velocities of these primary fragments range between 0.02 and 0.3 m s{sup -1}, comparable to the {approx}0.08 m s{sup -1} gravitational escape speed from the nucleus. Their sizes are on the order of decimeters or larger. We obtain the best fits to our data with ejection velocity vectors lying in a plane that includes the nucleus. This may suggest that the cause of the disruption of P/2010 A2 is rotational breakup.
- OSTI ID:
- 22126626
- Journal Information:
- Astrophysical Journal, Vol. 769, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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