2004/07/16 by Keith S. Noll, Keith Noll, Denise C. Stephens +6 · 4 citations
Physics and Astronomy · #Astro and Planetary Science #Planetary Science and Exploration #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/424535
accepted for publication in the Astronomical Journal, November 2004 18 pages, 5 figuers
arxiv created 2004/07/16 · openalex publication_date 2004/11/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We have measured the separations and position angles of the two components of the binary trans-Neptunian object (58534) 1997 CQ 29 at eight epochs. From these data we are able to constrain the orbit and mass of this binary system. The best-fitting orbit has an orbital period of P = 312 ± 3 days. The orbital eccentricity is e = 0.45 ± 0.03 and the semimajor axis is a = 8010 ± 80 km. The mass of the system is surprisingly low at (0.42 ± 0.02) × 10 18 kg. To account for the observed brightness consistent with the low mass and a range of plausible densities, the geometric albedo must be very high; for an assumed density of 1000 kg m -3 , we find a red geometric albedo of p R = 0.37, an order of magnitude higher than has been generally assumed for trans-Neptunian objects. If objects with comparably high albedos are common in the Kuiper belt, estimates of the mass of the belt must be significantly reduced. The semimajor axis of (58534) 1997 CQ 29 's orbit is 2.8% of the Hill radius of the primary, a value strikingly similar to this same ratio in other trans-Neptunian binaries, main-belt binaries, and regular satellite systems.