Haser model CN, C2 and C3 production rates in some comets

Abstract

Emission fluxes of CN, C2 and C3 species observed in the coma of some comets are analysed in the framework of Haser model. CN, Cz and C3 production rates are determined using recently derived fluorescence efficiencies and dependence of CN, C2 and C3 production rates on the heliocentric distance is studied. Evidence for a burst type activity around January 15, 1974 in the post-perihelion period of comet Kohoutek (1973f) is observed.

Detection of Diatomic Carbon in 2I/Borisov

“…The flux ratio between C 2 (∆v = 0) and C 2 (∆v = 1) is about 1.9. This result is consistent with the fluorescence efficiency L/N of C 2 (∆v = 0) = 4.5×10 −23 erg s −1 and L/N of C 2 (∆v = 1) = 2.4 × 10 −23 erg s −1 (de Almeida et al 1989), which indicates that the C 2 (∆v = 0) emission should be about 1.9 times stronger than the emission of C 2 (∆v = 1). We consider this agreement to be additional evidence suggesting that our C 2 detections are real.…”

Evaluation of gas production rates in some comets

“…The g-value of 388 nm CN (0,O) band is obtained multiplying the listed radiance per column density at rh = 1 AU by 4n and the effect of heliocentric distance was incorporated by a g 0~ rhQ power law (Tatum, 1984). For other bands recently derived g-factors (see Table I of Almeida et al, 1989) were used. Columns l-5 of Table I are self-explanatory and list observational parameters of comets Bennett (196913 197011), West (1975n = 1976VI), P Halley (1982i), Hartley-Good (19851) and Bradfield (1987s).…”

“…The derived CN, Cz and C3 production rates presented in Table I using recently obtained fluorescence efficiencies (Almeida et al, 1989) may have a systematic error amounting to about +20 percent and where possible these results were compared with the ones found in the literature. (Sekanina, 1982)), the expected errors should be at least twice as much since the data used (Sivaraman et al, 1979) corresponds to observations performed after the primary nucleus (A) of the comet had split in these four fragments close to perihelion passage (February 25.22, 1976 (UT)).…”

“…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).…”

“…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). Haser model analysis of CN, Cz and C3 production rates are developed for these comets and the possible logarithimic correlations among these molecular species and comets graphically analysed.…”