Temperature of Comet IRAS-Araki-Alcock (1983d)

Robert Hamilton Brown, Dale P. Cruikshank, David Griep

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5 Scopus citations


Infrared (1.5-20 μm) observations of the nuclear condensation of Comet IRAS-Araki-Alcock (1983d) during the interval 5-8 May 1983 (UT) show that the distribution of 3.5- to 20-μm radiation was blackbody in character with no evidence of 10-μm emission from silicate grains in the coma of the comet. The observed color temperature of the nuclear condensation of the comet was 319 ± 5°K on 7 May and 307 ± 5°K on 8 May. Low-resolution spectrophotometry on 5 May in the 1.5- to 2.6-μm region shows no obvious emission or absorption features, but thermal radiation of approximately the same color temperature as the 3.5- to 20-μm radiation was present along with reflected sunlight. Scans of the nuclear region of the comet indicate that most of the thermal radiation observed at 11.6 and 20.0 μm came from an ≤120-km-diameter, unresolved area centered on the nuclear region. Absolute flux measurements suggest that projected areas (unit emissivity) of 70 and 40 km2 were responsible for the thermal radiation from the nuclear condensation on 7 and 8 May, respectively. This large change in total surface area suggests that the amount of dust in the nuclear region of Comet 1983d was highly variable and is consistent with the observation by M.A. Feierberg, F.C. Witteborn, J.R. Johnson, and H. Campins (1984, Icarus, 60, 449-454) of an outburst on 11 May 1983.

Original languageEnglish (US)
Pages (from-to)273-281
Number of pages9
Issue number2
StatePublished - May 1985
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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