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A stellar occultation by Vanth, a satellite of (90482) Orcus
- Publication Year :
- 2018
- Publisher :
- arXiv, 2018.
-
Abstract
- A stellar occultation by the large trans-Neptunian object (90482) Orcus was predicted to occur on 2017 March 07. Observations were made at five sites in North and South America. High-speed, visible-wavelength images were taken at all sites, in addition to simultaneous K-band images at one location. Solid-body occultations were observed from two sites. Post-event reconstruction suggested an occultation of two different stars observed from two different sites. Follow-up, speckle imaging at Gemini Observatory revealed a second star, which verified that the occulting body in both cases was Orcus` satellite, Vanth. The two single-chord detections, with an anomalously large timing delay in one chord, have lengths of 291+/-125 km and 434.4+/-2.4 km. The observations, combined with a non-detection at a nearby site, allow a tight constraint of 443+/-10 km to be placed on Vanth`s size (assuming it is spherical). A 3-{\sigma} upper limit of 1-4 {\mu}bar (depending on constituent) is found for a global Vanth atmosphere. The immersion and emersion profiles are slightly different, with atmospheric constraints 40 percent higher on immersion than on emersion. No rings or other material were detected within ten thousand kms of Vanth, and beyond 8010 km from Orcus, to the tightest optical depth limit of approximately 0.1 at 5 km scale. The occultation probed as close as 5040 km from Orcus, placing an optical depth limit of approximately 0.3 at 5 km scale on any encircling material at that distance.<br />Comment: 37 Pages; 12 Figures; 3 Tables
- Subjects :
- Earth and Planetary Astrophysics (astro-ph.EP)
010504 meteorology & atmospheric sciences
Infrared telescope
Astronomy
FOS: Physical sciences
Astronomy and Astrophysics
01 natural sciences
Occultation
law.invention
Telescope
Stars
Photometry (astronomy)
Space and Planetary Science
law
Observatory
0103 physical sciences
Trans-Neptunian object
010303 astronomy & astrophysics
Geology
Optical depth
Astrophysics - Earth and Planetary Astrophysics
0105 earth and related environmental sciences
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....6dc28a6b631e1131e88534d416f218e2
- Full Text :
- https://doi.org/10.48550/arxiv.1810.08977