Update on Spacewatch Observations of Near-Earth Objects
Abstract
Spacewatch performs targeted astrometric follow-up of near-Earth objects, primarily asteroids (NEAs), to improve knowledge of their orbits. We have a noteworthy history of asteroid and comet observations beginning in 1984 as the first survey to use CCDs to scan the sky for asteroids and comets. Currently, we measure simultaneous astrometry and photometry of observations during an average of 24 nights per lunation (dark and gray time) as the exclusive users of a 1.8-m telescope and a 0.9-m telescope on Kitt Peak. In addition, we use bright time on the 2.3-m Bok Telescope and the 4-m Mayall Telescope on Kitt Peak to chase fainter targets. Continued astrometric follow-up helps to prevent potentially hazardous objects and scientifically interesting NEAs from becoming lost.We prioritize virtual impactors, MPC confirmation page objects, potentially hazardous asteroids (PHAs) with close approaches within 0.03 AU in the next 30 years, upcoming radar targets with astrometry requests, Yarkovsky effect candidates, NEAs with existing characterization data (WISE, Spitzer, SMASS, MANOS), possible spacecraft destinations (NHATS), and requests from the community.In mid October 2015, we switched from survey mode to targeted astrometry on the 0.9-m telescope. From 2015 October 15 through 2017 June 29 (1.7yr), Spacewatch (observatory codes 291, 691, and ^695) had 20951 MPC-accepted NEO lines of astrometry corresponding to measurements of 2647 different NEOs. This includes 4801 PHA lines of astrometry corresponding to 426 different PHAs, of which 223 lines were at apparent magnitudes V>=22.5. We observed 43% of all NEAs and 52% of all unnumbered NEAs that were observed by any observatory during that period. We observed 50% of all PHAs and 64% of all unnumbered PHAs observed during that period. These statistics do not include submitted measurements of confirmation page objects that were not confirmed as NEAs.Support of Spacewatch is from NASA/NEOO grants, the Lunar and Planetary Laboratory, Steward Observatory, Kitt Peak National Observatory, the Brinson Foundation of Chicago, IL, the estates of R. S. Vail and R. L. Waland, and other private donors. We are also indebted to the MPC and JPL for their web services.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #49
- Pub Date:
- October 2017
- Bibcode:
- 2017DPS....4911208B