Volume 473, Number 3, October III 2007
|Page(s)||L33 - L36|
|Published online||04 September 2007|
Letter to the Editor
E-type asteroid (2867) Steins: flyby target for Rosetta
Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Observatoire de Paris, 77 avenue Denfert-Rochereau, 75014 Paris Cedex, France e-mail: [Mirel.Birlan]@imcce.fr
2 Astronomical Institute of the Romanian Academy, 5 Cuţitul de Argint, 040557 Bucharest, Romania e-mail: firstname.lastname@example.org
3 LESIA, Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon Cedex, France e-mail: [Antonella.Barucci;Pierre.Vernazza;Marcelo.Fulchignoni]@obspm.fr
4 Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge MA 02139, USA e-mail: email@example.com
Accepted: 27 August 2007
Aims.The mineralogy of the asteroid (2867) Steins was investigated in the framework of a ground-based science campaign dedicated to the future encounter with Rosetta spacecraft.
Methods.Near-infrared (NIR) spectra of the asteroid in the 0.8-2.5 μm spectral range have been obtained with SpeX/IRTF in remote-observing mode from Meudon, France, and Cambridge, MA, in December 2006 and in January and March 2007. A spectrum with a combined wavelength coverage from 0.4 to 2.5 μm was constructed using previously obtained visible data. To constrain the possible composition of the surface, we constructed a simple mixing model using a linear (areal) mix of three components obtained from the RELAB database. A space-weathering model was applied to the aubrite ALH-78113 spectrum.
Results.The four new NIR spectra reveal no major absorption features. The best-fit model for the constructed visible-plus-NIR spectrum is represented by a mixture of 57% enstatite, 42% oldhamite, and 1% orthopyroxene. These results place Steins in a subdivision of the E-type class with objects like Angelina, Eger, and Nereus. This group is not sampled by the current collection of aubrite meteorites. Interestingly, the reddened aubrite spectrum also provides a good match to the Steins VNIR spectrum.
Key words: minor planets, asteroids / techniques: spectroscopic / methods: observational
© ESO, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.