A search for rotational variations on trans-Neptunian objects^*

LESIA, Observatoire de Paris, 92195 Meudon Cedex, France e-mail: alvaro.alvarez@obsmp.fr

Received: 20 June 2007
Accepted: 10 September 2007

Abstract

Aims.Our aim is to investigate the surface composition of TNOs. In particular we would like to confirm diverse spectral absorption features and to search for rotational inhomogeneities on one scattered disk object (26375) 1999 DE₉, two plutinos (38628) Huya and (47932) 2000 GN₁₇₁, and one centaur (83982) Crantor.

Methods.We observed the targets with a new instrument available at the VLT, the near-infrared integral field spectrograph SINFONI. We obtained complete near-infrared spectra between 1.4 and 2.4 μm and compared them with data recorded previously by various groups.

Results.Two objects, (38628) Huya and (83982) Crantor, have evidence of an absorption feature in their spectra at 2.0 μm, probably associated with water ice. (83982) Crantor shows a feature at 2.3 μm which could be associated with methanol. On the other hand, no features were found for (26375) 1999 DE₉ and (47932) 2000 GN₁₇₁ above the signal-to-noise ratio.
Possible rotational heterogeneity can be seen on two objects: (38628) Huya as the 2.0 μm band is present on some spectra and absent on others, while (47932) 2000 GN₁₇₁ shows a flat reflectance in contrast to an absorption in the H region previously seen.