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arXiv · 0911.5625

Optical polarimetry and photometry of comet 17P/Holmes

U. C. Joshi·S. Ganesh·K. S. Baliyan
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Abstract

Comet 17P/Holmes was observed for linear polarisation using the optical polarimeter mounted on the 1.2m telescope atop Gurushikhar peak near Mt. Abu during the period November-December 2007. Observations were conducted through the IHW narrow band (continuum) filters. During the observing run the phase angle was near $13^{\circ}$ at which the comet showed negative polarisation. On the basis of the observed polarisation data we find comet 17P/Holmes to be a typical comet with usual dust characteristics. We note that radial rate of change of brightness in coma in red band is higher than that in blue band; it has decreased by a factor of 3.6 and 2.5 respectively in red and blue bands during the November - December run, indicating relative increase in the abundance of smaller dust particles out ward. Radial brightness variation seen near the nucleus on November 6 is indicative of the presence of a blob or shocked region beyond 10" from the nucleus which has gradually smoothened by December 13. The brightness distribution is found steeper during November 5-7 as compared to on December 13.

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U. C. Joshi, S. Ganesh, K. S. Baliyan. 2009-11-30. Optical polarimetry and photometry of comet 17P/Holmes. https://doi.org/10.1111/j.1365-2966.2009.16096.x

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