Optical observations of Comet 67P/Churyumov-Gerasimenko^*

¹ Institute of Planetary Research, DLR, Rutherfordstrasse 2, 12489 Berlin, Germany
² Optical Information Systems and Space Sensor Technologies, DLR, Rutherfordstrasse 2, 12489 Berlin, Germany

Corresponding author: M. Weiler, michael.weiler@dlr.de

Received: 5 August 2003
Accepted: 13 October 2003

Abstract

From longslit spectra obtained during the 1996 perihelion passage of Comet 67P/Churyumov-Gerasimenko, a CN production rate of  molecules  was determined and an upper limit for the  production rate of  molecules  was derived. The dust color and dust activity were determined from the continuum light in the spectra. A neutral dust color was determined between 4070 Å and 4600 Å. The CN production rate and the Afρ  parameter, determined to  cm, were similar to the values of the 1982 perihelion passage, indicating that the comet's activity did not change significantly in recent orbital passages. A first crude estimate of the dust production rate indicates a high dust to gas mass ratio.
R-filter images taken in March 2003 were used to study the dust coma morphology. Two jet structures were seen in the coma; these structures show no variations within the observing period from March 7 to May 30, 2003. The orientation of these stationary structures suggests an inclination of the rotation axis of the nucleus of approximately  with respect to the orbital plane.