Spectral properties of eight near-Earth asteroids^⋆

¹ Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Observatoire de Paris, 77 avenue Denfert-Rochereau, 75014 Paris Cedex, France
e-mail: mpopescu@imcce.fr
² Polytechnic University of Bucharest, Faculty of Applied Sciences, Department of Physics, Bucharest, Romania
³ Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
⁴ Laboratoire d’Astrophysique de Marseille, Université de Provence-CNRS, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France
⁵ LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon Principal Cedex, France
⁶ Astronomical Institute of the Romanian Academy, 5 Cuţitul de Argint, 040557 Bucharest, Romania
⁷ Université Paris Diderot – Paris 7, 4 rue Elsa Morante, 75013 Paris, France
⁸ European Southern Observatory, K. Schwarzschild-Str. 2, 85748 Garching, Germany
⁹ Bucharest Astroclub, B-dul LascarCatargiu 21, sect 1, Bucharest, Romania

Received: 20 April 2011
Accepted: 21 July 2011

Abstract

Context. Near-Earth objects are among the most accessible bodies in the solar system in terms of the spacecraft propulsion requirements to reach them. The choice of targets and the planning of space missions are based on high quality ground-based science.

Aims. The knowledge of the ensemble of physical parameters for these objects, including their composition, is a critical point in defining any mission scientific objectives. Determining the physical properties of near-Earth asteroids (NEAs) is also possible from the ground by analyzing spectroscopy at both visible and infrared wavelengths.

Methods. We present spectra of eight NEAs (1917, 8567, 16960, 164400, 188452, 2001 SG286, and 2010 TD54) obtained using the NASA telescope IRTF equipped with the spectro-imager SpeX. The observations were performed in the 0.8–2.5 μm spectral region using the low resolution mode of the spectrograph. We completed the taxonomic classification using the Bus-DeMeo taxonomy. We analyzed the spectra by comparing them to meteorite spectra from the Relab database using a χ² approach. For the S-type asteroids of our sample, the band centers and BAR were calculated. We also attempted to interpret our data using a space-weathering model.

Results. The taxonomic classification of five objects was reviewed and we assigned a corresponding type to the other three asteroids that were not classified before. We found that (1917) Cuyo, (8567) 1996 HW1, (16960) 1998 QS52, (188452) 2004 HE62, and 2010 TD54 are in the S-complex. We achieved a good matching of our S-type asteroids with the spectra of ordinary chondrites meteorites. The asteroid (5620) Jasonwheeler was found to have a NIR spectrum similar to carbonaceous chondrite meteorites. Thus, our results confirm its primitive properties obtained in several other spectral intervals.