Near-infrared spectrophotometric observations of periodic comet Halley (1982i)

Periodic comet Halley (1982i) was observed spectrophotometrically in selected wavelength ranges between 2.0 and 3.5 μm with spectral resolutions of 170 to 270 on 1985 November 28 and 1986 January 3 and March 21-25. Although no molecular emission feature has been detected in the spectra observed, upper limits for the production rates of CO and CH4 have been obtained. A notable day-to-day variation of the near-infrared brightness of the inner coma was observed, consistent with an apparent periodicity of 2.4 d in dust producing activity. The dust production rate of about 2 to 5 x 106 gs-1 has also been derived by assuming the mean grain radius of 1 μm. (author)