EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 462/ 1 Article

Free access article

Issue A&A
Volume 462, Number 1, January IV 2007
Page(s) L13 - L16
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20066694



A&A 462, L13-L16 (2007)
DOI: 10.1051/0004-6361:20066694

Letter

Determination of the light curve of the Rosetta target asteroid (2867) Steins by the OSIRIS cameras onboard Rosetta

M. Küppers1, S. Mottola2, S. C. Lowry3, M. F. A'Hearn4, C. Barbieri5, M. A. Barucci6, S. Fornasier5, 6, O. Groussin4, 7, P. Gutiérrez8, S. F. Hviid1, H. U. Keller1, and P. Lamy7

1  Max-Planck-Institut für Sonnensystemforschung, Germany
    e-mail: kueppers@mps.mpg.de
2  Institute of Planetary Research, DLR, Germany
3  Astrophysics Research Centre, Queen's University Belfast, UK
4  Department of Astronomy, University of Maryland, USA
5  Dipartimento di Astronomia and CISAS, Università di Padova, Italy
6  University of Paris 7, France
7  Laboratoire d'Astrophysique de Marseille, France
8  Instituto de Astrofísica de Andalucía - CSIC, Spain

(Received 3 November 2006 / Accepted 30 November 2006)

Abstract
Context.In 2004 asteroid (2867) Steins has been selected as a flyby target for the Rosetta mission. Determination of its spin period and the orientation of its rotation axis are essential for optimization of the flyby planning.
Aims.Measurement of the rotation period and light curve of asteroid (2867) Steins at a phase angle larger than achievable from ground based observations, providing a high quality data set to contribute to the determination of the orientation of the spin axis and of the pole direction.
Methods.On March 11, 2006, asteroid (2867) Steins was observed continuously for 24 h with the scientific camera system OSIRIS onboard Rosetta. The phase angle was 41.7 degrees, larger than the maximum phase angle of 30 degrees when Steins is observed from Earth. A total of 238 images, covering four rotation periods without interruption, were acquired.
Results.The light curve of (2867) Steins is double peaked with an amplitude of $\approx$0.23 mag. The rotation period is $6.052~\pm\,\,0.007$ h. The continuous observations over four rotation periods exclude the possibility of period ambiguities. There is no indication of deviation from a principal axis rotation state. Assuming a slope parameter of G = 0.15, the absolute visual magnitude of Steins is $13.05 \pm 0.03$.


Key words: minor planets, asteroids -- techniques: photometric



© ESO 2007

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.