Optical polarimetry of Comet NEAT C/2001 Q4

• Published in: Icarus (New York, N.Y. 1962) Vol. 201; no. 2; pp. 666 - 673
• Main Authors: Ganesh, S., Joshi, U.C., Baliyan, K.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.06.2009; Elsevier
• Subjects: Astronomy; Comets; composition; dust; Earth, ocean, space; Exact sciences and technology; Polarimetry; Solar system; Comets; Polarimetry; Continuum; composition; Color; Cometary coma; Linear polarization; Solar system; dust
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2009.01.008

Comet NEAT C/2001 Q4 was observed for linear polarization using the optical polarimeter mounted at the 1.2 m telescope at Mt. Abu Observatory, during the months of May and June 2004. Observations were conducted through the International Halley Watch narrow band (continuum) and BVR broad band filters. During the observing run the phase angle ranged from 85.6° in May to 55° in June. As expected, polarization increases with wavelength in this phase angle range. Polarization colour in the narrow bands changes at different epochs, perhaps related to cometary activity or molecular emission contamination. The polarization was also measured in the cometary coma at different locations along a line, in the direction of the tail. As expected, we notice minor decrease in the polarization as photocenter (nucleus) is traversed while brightness decreases sharply away from it. Based on these polarization observations we infer that the Comet NEAT C/2001 Q4 has high polarization and a typical grain composition—mixture of silicates and organics.