The Mutual Orbit, Mass, and Density of the Large Transneptunian Binary System Varda and Ilmarë

Abstract

From observations by the Hubble Space Telescope, Keck II Telescope, and Gemini North Telescope, we have determined the mutual orbit of the large transneptunian object (174567) Varda and its satellite Ilmarë. These two objects orbit one another in a highly inclined, circular or near-circular orbit with a period of 5.75 days and a semimajor axis of 4810 km. This orbit reveals the system mass to be (2.664 +/- 0.064) x 10^20 kg, slightly greater than the mass of the second most massive main-belt asteroid (4) Vesta. The dynamical mass can in turn be combined with estimates of the surface area of the system from Herschel Space Telescope thermal observations to estimate a bulk density of 1.24 +0.50 -0.35 g cm^-3. Varda and Ilmarë both have colors similar to the combined colors of the system, B-V = 0.886 +/- 0.025 and V-I = 1.156 +/- 0.029.

16 pages, 4 tables, 6 figures, in press in Icarus

References in corpus (10)

• "TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations
• Formation of pebble-pile planetesimals
• The Correlated Colors of Transneptunian Binaries
• Masses of Nix and Hydra
• The orbit, mass, size, albedo, and density of (65489) Ceto/Phorcys: A tidally-evolved binary Centaur
• (42355) Typhon-Echidna: Scheduling Observations for Binary Orbit Determination
• Mutual Orbits and Masses of Six Transneptunian Binaries
• Rotational properties of the binary and non-binary populations in the Trans-Neptunian belt
• Angular Momemtum of Binary Asteroids: Implication for their possible origin
• Binaries in the Kuiper Belt

Cited by in corpus (15)

• "TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations
• Trans-Neptunian binaries (2018)
• Discovery of a satellite of the large trans-Neptunian object (225088) 2007OR10
• An Analytical Theory for the Growth from Planetesimals to Planets by Polydisperse Pebble Accretion
• The large Trans-Neptunian Object 2002 TC${}_{302}$ from combined stellar occultation, photometry and astrometry data
• Physical properties of the trans-Neptunian object (38628) Huya from a multi-chord stellar occultation
• Beyond Point Masses. III. Detecting Haumea's Nonspherical Gravitational Field
• The Upcoming Mutual Event Season for the Patroclus - Menoetius Trojan Binary
• The visible and thermal light curve of the large Kuiper belt object (50000) Quaoar
• The 2017 May 20${}^{\mathrm{th}}$ stellar occultation by the elongated centaur (95626) 2002 GZ${}_{32}$
• Can the gravitational effect of Planet X be detected in current-era tracking of the known major and minor planets?
• Low rock mass fraction within trans-Neptunian objects inferred from the spin-orbit evolution of Orcus-Vanth and Salacia-Actaea
• The Luminosity Function of Ultra-Faint Trans-Neptunian Objects Detected by JWST
• The resilience of the sailboat stable region
• A new multiple-arc model of the resonant Kuiper belt objects -- Plutinos