Nucleus of Comet Halley from Giotto

What Does the Image Show?
The image, taken from the Giotto spacecraft near closest encounter in 1986, shows the mantled surface of the nucleus of comet Halley. The sun is to the upper left in this picture. The night-side of the nucleus is visible to the lower right. It is seen in projection against sunlight scattered from the near-nucleus coma. Strong outgassing from a vent is seen at upper left, as well as several fainter vents on the day-side. However, most of the nucleus surface appears to be inactive even when in full sunlight, and this is because of a non-volatile mantle, probably a rubble mantle.

The mantle albedo (reflectivity) is about 4%, indicating a non-icy, probably carbon rich composition.

The lumpy appearance of the nucleus is real. Perhaps the lumps, and the elongated shape (16 x 8 x 8 km) tell us something about the internal structure of the nucleus.

Last updated December 1997

Nucleus	Comet	Jewitt