Surface features and the rotation state of Halley's comet nucleus.
Abstract
For the first time, the Vega 1 and Vega 2 spacecraft have observed the solid nucleus of a comet, on 6 and 9 March 1986. The transmitted images allow a unique description of the shape and the movement of comet Halley nucleus. The contours of the nucleus are compared with an elongated ellipsoid. The previous determination of the long axis orientation during the 2 encounters is confirmed. Moreover, these contours display several surface details. The rotation state of the nucleus is dominated by the motion around an axis which seems perpendicular to the long axis, with a period equal to 53.5 h. The comparison of Vega 1, Vega 2 and Giotto images shows that the 7.4 days period derived from several ground-based observations cannot be explained by a complete rotation motion around the long axis of the nucleus. But this rotation can be limited to small oscillations, connected to the nodding of the long axis coming from the nutation.
- Publication:
-
Annales Geophysicae
- Pub Date:
- April 1989
- Bibcode:
- 1989AnGeo...7..129A
- Keywords:
-
- Comet Nuclei;
- Giotto Mission;
- Halley'S Comet;
- Surface Properties;
- Image Processing;
- Image Rotation;
- Vega Project;
- COMETS;
- HALLEY;
- COMET NUCLEI;
- SURFACE;
- FEATURES;
- ROTATION;
- OSCILLATIONS;
- SHAPE;
- SPACECRAFT OBSERVATIONS;
- PERIOD;
- IMAGERY;
- PHOTOGRAPHS;
- DIAGRAMS;
- VEGA 1 MISSION;
- VEGA 2 MISSION;
- GIOTTO MISSION;
- IMAGE PROCESSING;
- ANALYSIS;
- HYPOTHESES;
- Cometary Nuclei: Rotation;
- Cometary Nuclei: Figures;
- Comet 1986 III Halley