Activity of comet 103P/Hartley 2 at the time of the EPOXI mission fly-by

Abstract

Comet 103P/Hartley~2 was observed on Nov. 1-6, 2010, coinciding with the fly-by of the space probe EPOXI. The goal was to connect the large scale phenomena observed from the ground, with those at small scale observed from the spacecraft. The comet showed strong activity correlated with the rotation of its nucleus, also observed by the spacecraft. We report here the characterization of the solid component produced by this activity, via observations of the emission in two spectral regions where only grain scattering of the solar radiation is present. We show that the grains produced by this activity had a lifetime of the order of 5 hours, compatible with the spacecraft observations of the large icy chunks. Moreover, the grains produced by one of the active regions have a very red color. This suggests an organic component mixed with the ice in the grains.

11 pages, 7 figures, Icarus in press

References in corpus (5)

• Photometry of cometary nuclei: Rotation rates, colours and a comparison with Kuiper Belt Objects
• Spitzer Space Telescope Observations of the Nucleus of Comet 103P/Hartley 2
• Optical observations of 23 distant Jupiter Family Comets, including 36P/Whipple at multiple phase angles
• Rotation of Comet Hartley 2 from Structures in the Coma
• Dust observations of Comet 9P/Tempel 1 at the time of the Deep Impact