EDP Sciences
Free access
Volume 489, Number 1, October I 2008
Page(s) 455 - 458
Section Planets and planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:200810226
Published online 23 July 2008

A&A 489, 455-458 (2008)
DOI: 10.1051/0004-6361:200810226

Visible spectroscopy in the neighborhood of 2003EL61

N. Pinilla-Alonso1, J. Licandro2, and V. Lorenzi1

1  Fundación Galileo Galilei & Telescopio Nazionale Galileo, PO Box 565, 38700 S/C de La Palma, Tenerife, Spain
    e-mail: npinilla@tng.iac.es
2  Instituto de Astrofísica de Canarias, c/Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain

Received 20 May 2008 / Accepted 15 July 2008

Context. The recent discovery of a group of trans-neptunian objects (TNOs) in a narrow region of the orbital parameter space and with surfaces composed of almost pure water ice, being 2003 EL61 its largest member, promises new and interesting results about the formation and evolution of the TNb and the outer Solar System.
Aims. The aim of this paper is to obtain information of the surface properties of two members of this group ((24835) 1995 SM55, (120178) 2003 OP32) and three potential members (2003 UZ117, (120347) 2004 SB60 and 2005 UQ513) and to use that in order to confirm or reject their association.
Methods. We obtained visible spectra of five TNOs using the 3.58 m Telescopio Nazionale Galileo at the “Roque de los Muchachos Observatory” (La Palma, Spain).
Results. The spectra of the five TNOs are featureless within the uncertainties and with colors from slightly blue to red ( -2 < S' < 18%/0.1 $\mu$m). No signatures of any absorption are found.
Conclusions. We confirm the association of 1995 SM55 and 2003 OP32 with the group of 2003 EL61 as their spectra are almost identical to that of 2003 EL61. Only one of the three candidates, 2003 UZ117, can be considered as a possible member of the EL61-group, as its visible spectrum is compatible with a spectrum of a surface composed of almost pure water ice and no complex organics. The other two, 2004 SB60 and 2005 UQ513 are red and must be considered as interlopers.

Key words: Kuiper Belt -- solar system: formation -- techniques: spectroscopic

© ESO 2008