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Spectropolarimetry of Comet Halley

Published online by Cambridge University Press:  12 April 2016

N. Visvanathan ,
Z. Meglick  and
D.T. Wickramasinghe
N. Visvanathan
Affiliation:
Mount Stromlo and Siding Spring Observatories
Z. Meglick
Affiliation:
Mount Stromlo and Siding Spring Observatories
D.T. Wickramasinghe
Affiliation:
Department of MathematicsAustralian National University

Abstract

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Spectropolarimetric observations from 3800 to 7000 Å were obtained for the nucleus of comet Halley for nine nights during 1985-86. The observations were spaced over phase angle of 2 to 66 °. The continuum polarization without molecular-line contamination as well as the polarization of the molecular lines were evaluated. The plot of polarization versus the phase angle shows small negative polarization for angles less than 20°. The highest polarization measured for phase angle ≤ 66° is 19.6% .The lowest polarization of −2.0% has been measured at the phase angle ~ 10°. The variation of polarization with phase angle is nearly linear in the range 30 to 60° giving a slope of 0.4316% per degree. There is small dependence of polarization with the wavelength in the region 3800 to 6500Å. The polarization of the molecular bands CN, C3, C2(0,0) and C2 (1,0) have also been evaluated for the spectra of 15th December 1985, 18th and 19th March 1986 and 8th April 1986.

Type
Cometary Dust: Observations and Evolution
Information
International Astronomical Union Colloquium , Volume 126: Origin and Evolution of Interplanetary Dust , 1991 , pp. 245 - 248
Copyright
Copyright © Kluwer 1991

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