Letter to the Editor

Visible spectroscopy of extremely young asteroid families

¹ Observatório Nacional, Rua Gal. José Cristino, 77, 20921-400 Rio de Janeiro, Brazil e-mail: thais.mothe@on.br; thais.mothe@gmail.com
² Southwest Research Institute, 1050 Walnut St., Suite 300 Boulder, Colorado 80302, USA e-mail: davidn@boulder.swri.edu

Received: 9 April 2008
Accepted: 31 May 2008

Abstract

Context. Remotely identifying asteroid analogs of ordinary chondrites (OC) is difficult because the reflectance spectra of airless bodies can be modified by space weathering processes like micrometeorite impacts. Recently discovered extremely young asteroid families (ages ≤1 My) may not have suffered strong space weathering effects.

Aims. We study extremely young asteroid families to learn about the composition of main belt asteroids and the space weathering rate

Methods. Members of extremely young families were, for the first time, observed and taxonomically classified. Observations took place at the GEMINI telescopes, using the instrument GMOS.

Results. The taxonomic classes found in the families are Q, Sq and S. The Q-class is the best proxy for OC materials.

Conclusions. We discovered for the first time Q-type asteroids in the Main-belt. Also,asteroids with ≤1 My appear to have been only partially space weathered. These families are, therefore, very interesting targets for further observations in the near-infrared region.