Spectrophotometric study of periodic Comet Halley (1982i)

Abstract

Spectral scans of the head of periodic Comet Halley (19821) have been presented and analysed in detail in the optical region (hh3200-7000 8); for ten nights during pre-perihelion period. Emission features due to NH, CN, CH, Cs, and Cz molecules have been identified. The behaviour of the variation of different emission lines strength as a function of heliocentric distance has been investigated. It is found that the comet exhibits night-to-night variation of brightness. The abundances and production rates of CN and C2 species have also been derived.

Evaluation of gas production rates in some comets

“…As a part of the systematic programme-Determination of Gas and Dust Production Rates in Comets (GDPC) -going on in this laboratory (Almeida et al, 1989;Almeida, 1991), the emission band fluxes of cometary CN, C2 and C3 carbon bearing molecular species observed in the coma of comets Bennett (19693 = 197011), Babu and Saxena (1972), West (1975n = 1976VI), Sivaraman et al (1979, Goraya et al (1989aGoraya et al ( , 1989b, Hartley-Good (19851), Rautela et al, (1989), Bradfield (1987s), Rautela and Sanwal (1988), and Ojha and Joshi (1989) are analysed. These comets are studied in the framework of the Haser model (1957) by using recently derived fluorescence efficiencies (g-factors) at rh = 1 AU (Almeida et al, 1989) and appropriate numerical parameters which are known for the more prominent species CN, C, and C3 (Cochran, 1985).…”

Gas Production Rates in Comets

“…As a part of the systematic programme -Determination of Gas and Dust Production Rates in Comets (GDPC) -going on in this laboratory (Almeida et al, 1989;Almeida, 1991), the emission band fluxes of cometary CN, C2 and C3 carbon bearing molecular species observed in the coma of comets Bennett (1969i = 1970II) (Babu and Saxena, 1972) West (1975n = 1976 (Sivaraman et al, 1979), P/Halley (1982i) (Goraya et al, 1989a;1989b), Hartley-Good (1985£) (Rautela et al, 1989) and Bradfield (1987s) (Rautela and Sanwal, 1988;Ojha and Joshi, 1989) are analysed. These comets are studied in the framework of the Haser model 1957) by using recently derived fluorescence efficiencies (g-factors) at r^ = 1 AU Almeida et al, 1989) and appropriate numerical parameters which are known for the more prominent species CN, C2 and C3 (Cochran, 1985).…”