Spectrophotometry of Comet Austin (1982g) during post-perihelion period

Abstract

Spectrum scans have been obtained of the head of Comet Austin on six nights at heliocentric distances (r) from 0.70 to 0.87AU. The useful spectral region is h&330-750nm. Strong emission features of CN (388nm) and Swan band sequence of C, (474, 516, and 563nm) were identified. Weak emission features of CH + C,(436 nm), C,(600nm), CN(420 nm) and CH + C,(405 nm) have also been found present. There is a change in the ratio of CN(388nm) to C,(516 nm) emission strength with increasing heliocentric distance. An estimate of the CN and C, abundances has been made and their production rates have been derived. The continuum of the comet is strongly reddened with reference to Sun. The continuum matches the scattered continuum of solar radiation according to hZ law (Mie scattering) closely.

Spectrophotometric observations of Comet Austin (1982g)

“…The production rates we have computed can be compared with those derived by Goraya et al (1984). Using their Figure 3, we estimate a production rate for C2 for about 1O26 SK', in excellent agreement with our estimate.…”

“…For C, we find N = 4.74 x 1030 molecules, while for C, we get N = 6.5 x 1O29 molecules. The value for C, is close to the value obtained by Goraya et al (1984). Since the CN emission is considerably asymmetric, the results of such calculations are unlikely to be reliable for the CN molecules.…”

“…The relatively bright comet Austin (19828) unfortunately did not attract much attention from observers. Besides short communications by McCracken and Brown (1982), there is only one detailed spectrophotometric work by Goraya et al (1984). These observations cover the perihelion and near perihelion period.…”