ESO large program about transneptunian objects: surface variations on (47171) 1999 TC₃₆^*

¹ Max-Planck-Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany e-mail: protopapa@mps.mpg.de
² LESIA, Observatoire de Paris, 92195 Meudon Principal Cedex, France
³ INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy

Received: 11 July 2008
Accepted: 8 February 2009

Abstract

Aims. We investigate the surface composition of the Plutino (47171) 1999 TC₃₆.

Methods. We completed near-infrared photometric and spectroscopic observations of (47171) 1999 TC₃₆ with the adaptive optics instrument NACO at the ESO VLT during 12 October 2006, and present these data with ISAAC and SINFONI spectroscopic observations carried out about one month later on 9 November 2006 and 8 November 2006, respectively. The ISAAC and SINFONI spectroscopic observations were combined with a visible spectrum obtained by FORS1 on 9 November 2006. Composition and properties of the compounds present on the surface of the target are investigated by applying a Hapke radiative transfer model to the measured spectra and to previously published observations.

Results. We present the relative reflectance spectrum of (47171) 1999 TC₃₆ in the wavelength range (0.37–2.33) μm. An intimate mixture of Triton tholin, Titan tholin, serpentine, and Triton tholin diluted in water ice represents the best-fit model description of the measured spectrum. Any significant differences from the published spectra of (47171) 1999 TC₃₆ taken on 2001 and 2003 could be due to surface heterogeneity.