A 2017 stellar occultation by Orcus/Vanth
Abstract
(90482) Orcus is a large trans-Neptunian object (TNO) of diameter ~900 km, located in the 3:2 orbital resonance with Neptune. This plutino has a satellite, Vanth, approximately 280 km in diameter. Vanth orbits roughly 9000 km from Orcus in a ~9.5-day period. This system is particularly interesting, as Orcus falls between the small, spectrally-bland TNOs and the large TNOs having spectra rich in volatile features, while Vanth might have resulted from either collision or capture.A stellar occultation by Orcus was predicted to occur on 07 March 2017. Observations were made from five sites: the 0.6-m Astronomical Telescope of the University of Stuttgart (ATUS) at Sierra Remote Observatories (SRO), California; Las Cumbres Observatory’s 1-m telescope (ELP) at McDonald Observatory, Fort Davis, Texas; NASA’s 3-m InfraRed Telescope Facility (IRTF) on Mauna Kea, Hawaii; the 4.1-m Southern Astrophysical Research telescope (SOAR) on Cerro Pachón, Chile; and the 0.6-m Southeastern Association for Research in Astronomy telescope (SARA-CT) at Cerro Tololo, Chile. High-speed, visible-wavelength images were taken at all sites, in addition to simultaneous K-band images at the IRTF. A solid-body occultation was observed at both ELP and the IRTF. Offset midtimes and incompatible light ratios suggest that two different stars were occulted by two different bodies, likely Orcus and Vanth. See Bosh et al. this conference for details of the astrometry for the event. Here, we present results from the observations, including light curves, size and albedo estimates, and upper limits on a possible atmosphere.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #49
- Pub Date:
- October 2017
- Bibcode:
- 2017DPS....4921602S