Physical Characterization of Deep Impact Flyby Target (163249) 2002 GT
Abstract
We report on the ongoing physical characterization campaign for near-Earth asteroid (163249) 2002 GT, the target of a Deep Impact spacecraft flyby set for Jan. 2020. With a collaboration of over 45 colleagues we have gathered a wide range of observational data that inform us of the nature of this sub-km PHA. We have gathered spectra at UV, VIS and NIR wavelengths, which point to a Q or Sq taxonomic type with visible albedo 25% or higher. Visible photometry yields an absolute magnitude H = 18.71 ± 0.17, which taken together with the albedo constraint implies an effective diameter 350-500 m. Arecibo radar observations are consistent with this size range, and radar delay measurements have significantly improved the orbit. Photometric light curves have constrained the rotation period to P=3.7663±0.0007 h and indicate an elongation ratio >1.16. Of particular importance is a series of unambiguous attenuations seen in some of the light curves, presumably due to eclipse or occultation events from a secondary component. The magnitude of the attenuations indicates a secondary/primary size ratio ~0.3, and the lack of a secondary detection with Arecibo implies a size ratio <0.5. We will report on attempts to resolve a possible companion to 2002 GT with both Keck Adaptive Optics and Hubble Space Telescope imaging. The June 2013 apparition was the last time 2002 GT will be brighter than magnitude 18 until after the 2020 spacecraft flyby and thus represents a unique opportunity to characterize this potential space mission target. The information gained from this effort will aid planning and development of the flyby imaging sequence and interpretation of associated imagery.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #45
- Pub Date:
- October 2013
- Bibcode:
- 2013DPS....4510106P