Selecting asteroids for a targeted spectroscopic survey ^⋆

¹ Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland
e-mail: dagmara.oszkiewicz@gmail.com
² Nicholaus Copernicus University, ul. Gagarina 11, 87-100 Toruń, Poland
³ IMCCE - Paris Observatory – UMR 8028 CNRS 77, av. Denfert-Rochereau, 75014 Paris, France
⁴ Astronomical Institute of the Romanian Academy, Strada Cutitul de Argint 5, 040557 Bucureti, Romania
⁵ Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain
⁶ Division of Geophysics and Astronomy, Department of Physics, PO Box 64, 00014 University of Helsinki, Finland

Received: 13 December 2013
Accepted: 15 August 2014

Abstract

Context. Asteroid spectroscopy reflects surface mineralogy. There are a few thousand asteroids whose surfaces have been observed spectrally. Determining their surface properties is important for many practical and scientific applications, such as developing impact deflection strategies or studying the history and evolution of the solar system and planet formation.

Aims. The aim of this study is to develop a preselection method that can be used to search for asteroids of any taxonomic complex. The method could then be utilized in multiple applications, such as searching for the missing V-types or looking for primitive asteroids.

Methods. We used the Bayes Naive Classifier combined with observations obtained in the course of the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer surveys, as well as a database of asteroid phase curves for asteroids with a known taxonomic type. With this new classification method, we selected a number of possible V-type candidates. Some of the candidates were then spectrally observed at the Nordic Optical Telescope and South African Large Telescope.

Results. We developed and tested the new preselection method. We found three asteroids in the mid-to-outer main belt that probably have differentiated types. Near-infrared observations are still required to confirm this discovery. As in other studies we found that V-type candidates cluster around the Vesta family and are rare in the mid-to-outer main belt.

Conclusions. The new method shows that even largely explored large databases when combined could still be exploited further in, for example, solving the missing dunite problem.