Recovery and Evidence for Rapid Rotation of Manned Mission Candidate 2001 QJ142
Abstract
The near-Earth asteroid 2001 QJ142 falls high on the list of candidates for a manned mission due to the low delta-V needed to reach the target. The object was observed for only 32 days in 2001, leading to a three-sigma ephemeris uncertainty region spanning over 6 deg as of 2012 March 6, when the asteroid reached a peak brightness of V=22.6 during the opposition. We attempted recovery observations on February 16 using the Megaprime instrument on the Canada-France-Hawaii Telescope. Initial examination of the data did not reveal the target. A repeated recovery attempt was performed on February 27 using the Tektronix 2048 CCD camera on the University of Hawaii 2.24-m telescope. This latter attempt was successful, the object being found about 34 arcmin east of the nominal ephemeris position. Multiple 300 sec exposures consistently revealed the asteroid. We reexamined the Megaprime images to determine why the object was not found during the initial recovery attempt. The object was clearly detected in just one of the 140 sec exposures, but could be barely seen in the other two exposures at a signal-to-noise ratio of just 2. Apparently the asteroid has a large lightcurve amplitude and a short rotation period. The 300 sec exposures on February 27 apparently averaged over enough of the lightcurve to produce a fairly uniform brightness, while the 140 sec exposures on February 16 did not. These results suggest a rotation period of about 10 min, making a manned mission problematic, except for regions of the surface near the poles. We are working on integrating sample lightcurves over the known exposure times in an attempt to refine the rotation period. It should be noted that another observational window occurs in late November when the asteroid reaches V=20.9 during its next opposition. This work was supported by NSF.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #44
- Pub Date:
- October 2012
- Bibcode:
- 2012DPS....4411112T