Evaluating the carbon depletion found by the Stardust mission in Comet 81P/Wild 2

¹ Department of PhysicsUniversity of Helsinki, PO Box 64, 00014 Helsinki, Finland
e-mail: ezubko@rambler.ru
² Institute of Astronomy, Kharkov National University, 35 Sumskaya St., 61022 Kharkov, Ukraine
³ Finnish Geodetic Institute, PO Box 15, 02431 Masala, Finland
⁴ Université Pierre & Marie Curie, LATMOS, 11 Bd. D’Alembert, 78280 Guyancourt, France
⁵ Université Pierre & Marie Curie, LATMOS, BC 102, 4 place Jussieu, 75005 Paris, France
⁶ Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
⁷ US Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA

Received: 7 February 2012
Accepted: 19 July 2012

Abstract

The low abundance of refractory carbonaceous material in samples collected by Stardust in comet 81P/Wild 2 coma was completely unexpected. If these results are universal to other comets, this necessitates a reformulation of current models of solar system formation. A polarimetric imaging analysis demonstrates that dust is not uniformly distributed within cometary coma, and that the circumnucleus halo region where the dust samples were collected must contain a low population of carbonaceous particles. Such regions are seen in other comets, suggesting that comet 81P/Wild 2 is not unusual and that the anomalous lack of carbon is not necessarily representative of the entire coma.