A&A 422, L19-L21 (2004)
DOI: 10.1051/0004-6361:20040190

Letter

Rosetta target comet 67P/Churyumov-Gerasimenko

Postperihelion gas and dust production rates

R. Schulz¹, J. A. Stüwe² and H. Boehnhardt<sup>3

1</sup>  ESA Research and Scientific Support Department, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
    e-mail: Rita.Schulz@rssd.esa.int
²  Sterrewacht Leiden, Postbus 9513, 2300 RA Leiden, The Netherlands
    e-mail: stuwe@strw.leidenuniv.nl
³  Max-Planck-Institute for Aeronomy, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
    e-mail: hboehnha@linmpi.mpg.de

(Received 19 March 2004 / Accepted 5 June 2004)

Abstract
The evolution of the activity and composition of the coma of ROSETTA target comet 67P/Churyumov-Gerasimenko was studied along its postperihelion orbit from 2.29 AU to 3.22 AU. The comet had a major drop of activity between 2.5 AU and 2.9 AU, which manifested most obviously in its light curve (the brightness decreased by 3 mag), but is also confirmed by the production rates derived from spectrophotometric measurements. The strong decrease of activity indicates a change in the outgassing behaviour of the nucleus and might be due to water sublimation becoming less efficient. The spectrophotometric measurements at 2.9 AU show that the coma is at least slightly depleted in C ₂ with respect to CN.

Key words: comets -- Rosetta -- 67P/Churyumov-Gerasimenko -- production rates

Offprint request: R. Schulz, Rita.Schulz@rssd.esa.int

© ESO 2004

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.