Astronomy and Astrophysics Supplement Series, Vol. 120, December I 1996, 301-311
Dust colors, dust release rates, and dust-to-gas ratios in the comae of six comets
G.C. Sanzovo , P.D. Singh and
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Department of Physics, State University of
Londrina, Perobal, 86051 Londrina, PR, Brazil
Southwest Research Institute, 6220 Culebra Road, P. O. Drawer 28510, San Antonio, TX 78228-0510, U.S.A.
On leave from Department of Astronomy, Institute of Astronomy and Geophysics, University of São Paulo, Av. Miguel Stefano 4200, Agua Funda, São Paulo, Cep. 04301-904, Brazil
Received February 9, 1995; accepted March 22, 1996
Abstract:In an attempt to find correlations between properties of comets, we determine the dust colors, dust release rates, and dust-to-gas mass ratios in the comae of Comets Bowell (1980 b = 1982 I), Bradfield (1979 l = 1979 X), Brorsen-Metcalf (1989 o = 1989 X), Giacobini-Zinner (1984 e = 1985 XIII), Levy (1990 c = 1990 XX), and Stephan-Oterma (1980 g = 1980 X) using a uniform and systematic analysis of the continuum fluxes measured at optical wavelengths. We assume that the continuum fluxes observed in these comets are from light scattered by micrometer-sized dust particles. The color of the dust is blue, relative to the Sun, in Comets Bradfield (1979 X) and Brorsen-Metcalf (1989 X); both comets have a low dust-to-gas mass ratio (). Comets Giacobini-Zinner (1985 XIII) and Stephan-Oterma (1980 X) have an intermediate dust-to-gas mass ratio (), whereas Comets Levy (1990 XX) and Bowell (1982 I) have a high dust-to-gas mass ratio (). The continuum flux from dust particles in comets with intermediate to high dust-to-gas mass ratios is in general red, relative to the Sun. However, the color changes to blue in these comets when the dust-to-gas mass ratios are low relative to their peak values.
Key words: comets --- Bowell (1982 I); Bradfield (1979 X); Brorsen-Metcalf (1989 X); Giacobini-Zinner (1985 XIII); Levy (1990 XX); Stephan-Oterma (1980 X)
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