Spacewatch Observations of Near-Earth Objects
Abstract
We have enhanced Spacewatch's (McMillan et al. 2007 IAU Symp. 236) astrometry and photometry of Near-Earth Objects (NEOs). We specialize in follow-up of the Congressionally-mandated "large" NEOs (absolute mag H≤22) as they recede from Earth after discovery and become fainter, as well as NEOs on impact risk pages, Potentially Hazardous Asteroids, and NEOs observed by WISE (Mainzer et al. 2012 ApJ 752, id 110). Spacewatch was the pre-eminent follower-up of NEOs discovered by WISE within 2 weeks of their discovery. We have observed at elongations as small as 46°. Follow-up on longer orbital arcs improves understanding of the statistics of the orbits and absolute magnitudes of the population as well as the recoverability of individual objects. The new CCD which we began operating on our 1.8-m telescope on 2011 Oct 16 makes 23rd mag asteroids more frequently accessible. Faster readout and smaller pixels yield 67% more observations of NEOs per year and astrometric residuals of ±0.3 arcsec, vs. ±0.6 arcsec on NEOs with the old CCD. To reach more distant objects with H≤22, we now also use the Bok 2.3-meter telescope of Steward Observatory and the Kitt Peak National Observatory (KPNO) 4-m Mayall telescope. About 2800 tracklets of NEOs were accepted by the MPC from Spacewatch in the interval 2011 Jul 1 - 2012 Jun 30. The archive of images collected with our mosaic of CCDs on the 0.9-m telescope of Steward Observatory now approaches 15 TB in size and spans almost 10 years of uniformly conducted surveying. It contributes incidental followup astrometry and precoveries of NEOs. This work is funded by NASA/NEOO grants NNX11AB52G and NNX12AG11G, the Brinson Foundation of Chicago, IL, the estates of R. S. Vail and R. L. Waland, and other private donors. Spacewatch uses facilities of KPNO and services of the IAU’s Minor Planet Center.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #44
- Pub Date:
- October 2012
- Bibcode:
- 2012DPS....4421014M