Credit: NASA, ESA, and H. Weaver (The Johns Hopkins
University/Applied Physics Lab) Hubble Probes Comet 103P/Hartley
2 in Preparation for DIXI/EPOXI Flyby › View larger image Hubble
Space Telescope observations of comet 103P/Hartley 2, taken on
September 25, are helping in the planning for a November 4 flyby
of the comet by NASA's Deep Impact eXtended Investigation (DIXI)
on NASA's Deep Impact Spacecraft performing the EPOXI mission."
Analysis of the new Hubble data shows that the nucleus has a
diameter of approximately 0.93 miles (1.5 km), which is
consistent with previous estimates. The comet is in a highly
active state, as it approaches the Sun. The Hubble data show
that the coma is remarkably uniform, with no evidence for the
types of outgassing jets seen from most "Jupiter Family" comets,
of which Hartley 2 is a Jets can be produced when the dust
emanates from a few specific icy regions, while most of the
surface is covered with relatively inert, meteoritic-like
material. In stark contrast, the activity