Istituto di Scienza e Tecnologie dell'Informazione     
Fulchignoni M., Vernazza P., Birlan M., Dotto E., Rossi A., Fornasier S., Marzari F., Nesvorny D. Spectroscopic characterization of the Karin family. In: 37th American Astronomical Society. DPS Meeting (Cambridge, Great Britain, 4 - 9 September 2005).
The Karin asteroidal family was firstly identified by Nesvorny et al. (2002, Nature 417) who numerically integrated the orbits of 39 known members. More recently Nesvorny and Bottke (2004) analyzed a wider sample of objects and, taking into account also the Yarkovsky effect, identified the common origin of 90 family members at 5.750.05 Myr in the past. This is an exceptionally young age for an asteroid family. In fact, other known families are thought to be much older, 100 Myr to Gyrs old. We carried out visible and near-infrared spectroscopy of several members of the Karin family. We observed 5 member of the Karin family on November 2003 using the IRTF telescope. These data confirm that 832 Karin is an S-type asteroid (as indicated by Binzel, private communication), characterized by strong absorption features of olivines and pyroxenes at about 1 and 2 mm. Spectra for 17 objects were later obtained in December, 2004 with the NTT (ESO, La Silla). Twelve of these objects (832 Karin among them), have S-type spectra with the maximum of each spectra located at a very similar wavelength. The five other spectra obtained seem rather primitive (B,C types). Our results does not allow us to have clear ideas concerning the genesis of the family of the Karin family. We believe that more data are fundamental in order to assess at least the following points : 1) are the five 'more primitive' members interlopers? 2) could they be included in the layer crust model of a differentiated parent body? 3) did we observe another family? Moreover, we inter-compare the spectra of the Karin members in order to i) assess the physico-chemical properties of these objects, ii) retrieve the maximum information about the nature of their parent body(ies), and iii) investigate the evolution of their surfaces and the alteration processes which may have modified their pristine surfaces.
Subject Asteroids
J.2 Physical Sciences and Engineering

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