Imaging Borrelly

• Published in: Icarus
• Main Authors: Soderblom, L.A., Boice, D.C., Britt, D.T., Brown, R.H., Buratti, B.J., Kirk, R.L., Lee, M., Nelson, R.M., Oberst, J., Sandel, B.R., Stern, S.A., Thomas, N.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2004
• Subjects: Institut für Planetenforschung; North Pole
• Online Access: https://elib.dlr.de/10907/

The nucleus, coma, and dust jets of short-period Comet 19P/Borrelly were imaged from the Deep Space 1 spacecraft during its close flyby in September 2001. A prominent jet dominated the near-nucleus coma and emanated roughly normal to the long axis of nucleus from a broad central cavity. We show it to have remained fixed in position for more than 34 hr, much longer than the 26-hr rotation period. This confirms earlier suggestions that it is co-aligned with the rotation axis. From a combination of fitting the nucleus light curve from approach images and the nucleus' orientation from stereo images at encounter, we conclude that the sense of rotation is right-handed around the main jet vector. The inferred rotation pole is approximately perpendicular to the long axis of the nucleus, consistent with a simple rotational state. Lacking an existing IAU comet-specific convention but applying a convention provisionally adopted for asteroids, we label this the north pole. This places the sub-solar latitude at ~60° N at the time of the perihelion with the north pole in constant sunlight and thus receiving maximum average insolation.