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Afrho
This plot shows the brightness of the dust coma, in terms of the Afrho parameter, with time. Professional measurements (diamonds) from the 1983, 1994, and 1999 apparitions and STSP measurements (crosses) from the 1999 and 2005 apparitions are plotted with respect to days from perihelion (Lisse et al., 2005, McLaughlin et al., 2003, and private communications with STSP participants, 2004-2005). The Afrho parameter (A'Hearn et al., 1984) is useful for long-term studies of the behavior of the dust coma because it removes variations introduced by changing heliocentric distances, geocentric distances, and aperture sizes. An Afrho measurement of 100 centimeters equates to about 100 kilograms of dust per second.
A'Hearn, M. F., D. G. Schleicher, P. D. Feldman, R. L. Millis, and D. T. Thompson, 1984. "Comet Bowell 1980b", Astronomical Journal, 89, 579-591.
Lisse, C.M., M.F. A'Hearn, T.L. Farnham, O. Groussin, K.J. Meech, U. Fink, and D.G. Schleicher, The Coma of Comet 9P/Tempel 1, Space Science Reviews (2005, in press).
McLaughlin, S.A., L.A. McFadden, and G. Emerson, 2003, Science with Very Small Telescopes (<2.4 meters): The NASA Deep Impact Mission's Small Telescope Science Program in The Future of Small Telescopes in the New Millenium, Volume III - Science in the Shadows of Giants, Ed. Terry D. Oswalt, Astrophysics and Space Science Library, Kluwer Academic Publishers, Volume 289, p. 57.
Afrho Plots for Tempel 1 and other comets
STSP Coordinator: Stef McLaughlin
Webmaster: Elizabeth Warner
Last Updated: Wednesday August 29, 2007
