Infrared monitoring of comet P/Halley
We present the results of an infrared monitoring program of comet P/Halley. Multiaperture photometry between 1 and 5 gm was obtained during 12 nights in the preperihelion phase from the Gornergrat observatory, and during 4 nights in the postperihelion phase from the ESO 1-m telescope at La Silla. In addition, 10 and 20 gm photometry was obtained on November 4 and 7, when the comet was at 1.88 AU from the Sun. An analysis of the JHK data indicates that Halley was typically somewhat redder than the Sun (<J−H> = 0.48, <H−K> = 0.18) and that its colors did not change throughout our monitoring period, implying that the properties of the dust in the coma remained constant. Also, with the exception of November 4 and March 21, when Halley was presumably undergoing an outburst, the multiaperture data are consistent with an r −2density distribution of scattering dust in the coma. Furthermore, the flux from Halley in its quiescent phase increased as R −4.5, where R is the heliocentric distance. The 10 gm silicate feature in emission was detected at about the 2σ level on 4 and 7 November, and from the spectral energy distribution at that time we deduced an albedo of 0.05 for the scattering dust in the coma.
Key wordsHalley’s comet infrared continuum dust: silicates
Unable to display preview. Download preview PDF.
- Campins, H., Hanner, M.S.: 1982, in Comets, ed. L. Wilkening, Univ. Arizona Press, Tucson, p. 341Google Scholar
- Dollfus, A., Suchail, J.-L., Crussaire, D., Killinger, R., 1986, in Exploration of Halley’s Comet, B. Battrick, E.J. Rolfe, R. Reinhard, ESA, Noordvijk, p. 41Google Scholar
- Fulle, M., Barbieri, C., Cremonese, G.: 1987 (preprint)Google Scholar
- Giese, R.H., Killinger, R.T., Kneissel, B., Zerull, R.H.: 1986, inGoogle Scholar
- Exploration of Halley’s Comet,eds. B. Battrick, E.J. Rolfe,R. Reinhard, ESA, Noordvijk, p. 131Google Scholar
- Hunt, L.: 1986, Oss. Astrofis. Arcetri. (internal note) Koornneef, J.: 1983, Astron. Astroph. Suppl. 51, 489Google Scholar
- Ney, E. P.: 1982, in Comets, L. Wilkening, Univ. Arizona Press, Tucson, p. 323Google Scholar
- Saraceno, P., Lorenzetti, D., Messi, R., Orfei, R.: 1982, in Proc. 2 °d ESO Infrared Workshop, A.F.M. Moorwood,K. Kjaer, p. 93Google Scholar