Last stop before close flyby – CometWatch 9 February

Today’s CometWatch entry is a single frame NAVCAM image taken on 9 February from a distance of 105 km from the comet centre. The image resolution is 8.9 m/pixel; the processed image below has been slightly cropped to eliminate vignetting in the upper corners, and measures 8.5 x 8.5 km (the original, provided at the end of the post, measures 9.1 x 9.1 km). In this orientation, the comet’s small lobe is the foreground and the large lobe is in the background. Particularly stunning is the delicate, ethereal glow of activity that contrasts against the shadowed region between the two lobes. From this viewing position the outflowing material seems to take the shape of a broader fan, rather than the more collimated jet-like features seen at other angles. As seen in previous images, the sharp vertical shadows seem to be a result of the large lobe casting shadows down across the neck of the comet and towards the head. There is very little back-scatter illumination around the neck itself, but a diffuse ‘glow’ can be seen against these dark shadows where a broader ‘atmosphere’ is visible above the surface of the small lobe. Rosetta is now less than 24 hours from its close 6 km flyby of the comet – closest approach tomorrow occurs at 12:41 GMT (13:41 CET) above the Imhotep region. The NAVCAM is scheduled to take images 1-2 hours before and after closest approach, when the spacecraft will be between about 8.5 and 11 km above the comet surface. These NAVCAM images will be downlinked to Earth Sunday/Monday and – depending on availability – we hope to be able to share one of these images with you as Monday’s CometWatch entry. Meanwhile the OSIRIS team expects to get their images back some 5-12 days after the flyby, […]



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