EDP Sciences
Free access
Volume 398, Number 1, January IV 2003
Page(s) 345 - 352
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20021673

A&A 398, 345-352 (2003)
DOI: 10.1051/0004-6361:20021673

Characterization of STARDUST target comet 81P/Wild 2 from 1996 to 1998

R. Schulz1, J. A. Stüwe2, H. Boehnhardt3, W. Gaessler4 and G. P. Tozzi5

1  Research and Scientific Support Department of ESA, ESTEC, Postbus 299, 2200 $\,$AC Noordwijk, The Netherlands
    e-mail: Rita.Schulz@esa.int
2  Sterrewacht Leiden, Postbus 9513, 2300 $\,$RA Leiden, The Netherlands
    e-mail: stuwe@strw.leidenuniv.nl
3  European Southern Observatory Chile, Alonso de Cordova 3107, Santiago, Vitacura, Chile
    e-mail: hboehnh@eso.org
4  Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720, USA
    e-mail: Wolfgang.Gaessler@SubaruTelescope.org
5  Osservatorio Astrophisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
    e-mail: tozzi@arcetri.astro.it

(Received 11 March 2002 / Accepted 5 November 2002 )

We present the results of our monitoring of comet 81P/Wild 2, the target of the STARDUST mission. Broad-band filter images and medium resolution spectra of this comet obtained along its pre- and postperihelion orbit between 1996 and 1998 were analysed in terms of coma morphology and activity. The morphological coma investigation revealed the presence of long-lasting fan structures, which remained essentially unchanged for at least three months. The ( B-V) and ( V-R) colour indices were determined at three different positions along the orbit. The two-dimensional analysis showed a uniform colour over the entire coma. Hence, the material composing the structures is not different from that of the underlying coma. The distribution of coma brightness as a function of projected distance from the nucleus shows no peculiarities. The evolution of the comet's activity during the pre- and postperihelion phase appears to be asymmetric in that activity increases faster preperihelion than it decreases postperihelion. The production rates (or their upper limits in the case on a non-detection) of CN, C 2, C 3, and NH 2 were determined from the spectrophotometric observations and compared to other values published in the literature.

Key words: comets: general -- comets: individual: 81P/Wild 2

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

© ESO 2003