Size, density, albedo and atmosphere limit of dwarf planet Eris from a stellar Occultation

B. SICARDY, J. L. ORTIZ, M. ASSAFIN, E. JEHIN, A. MAURY, E. LELLOUCH, R. GIL-HUTTON, F. BRAGA-RIVAS, Y OTROS.

Nantes

Congreso; EPSC-DPS Joint Meeting 2011; 2011

Europlanet

We report the observation of a multi-chord stellar occultation by the dwarf planet (136199) Eris. The event was observed on November 6, 2010 UT, from two sites in Chile. Our observation is consistent with a spherical Eris with radius R_E=1163 +-  6 km, density rho=2.52 +- 0.05 g cm^-3, and a visible geometric albedo p_v=0.96 + 0.09 - 0.04. Besides being remarkably similar in size to Pluto, Eris appears as one of the intrinsecally brightest objects of the solar system, with a density suggesting a mainly rocky interior. Upper limits of about 1 nbar are derived for the surface pressure of possible notrogen, argon or methane atmspheres of the dwarf planet.