The extra red plutino (55638) 2002 VE95

Abstract

Aims: In the framework of a large program, we observed (55638) 2002 VE95 with the ESO-VLT telescope to better constrain its surface composition and to investigate the possible heterogeneity of the surface. Methods: We report new near-infrared observations performed in 2007 and 2008. Using the new constraints of the albedo obtained by Herschel Space Observatory observations, a surface model was computed using the complete set of spectra (from visible to the near-infrared) as well as those of the previous published data to investigate the surface composition properties of (55638) 2002 VE95. Results: The surface is heterogeneous. This red object is covered by different icy compounds, such as water (4-19%) and methanol (10-12%). Different organic compounds, such as titan and triton tholins seem also to be present in the surface. The amount of the components is different depending on the observed area. That methanol ice seems to be present mainly on very red surface favors the hypothesis that surfaces of very red objects are more primordial. Based on observations made with ESO Very Large Telescope at the La Silla-Paranal Observatory under program ID 178.C-0036 (PI: A. Barucci) and the Herschel Space Observatory. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.