Neutral cometary atmospheres. II - The production of CN in comets

Abstract

view Abstract Citations (43) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Neutral cometary atmospheres. II - The production of CN in comets Combi, M. R. ; Delsemme, A. H. Abstract Brightness profiles of the CN (0-0) band at 3883 A have been constructed from spectrograms of comets Bennett (1979 II) and West (1976 VI). The subsequent analysis of these profiles shows that the parent molecule of CN had a radial scale length of (2.19 plus or minus 0.07) x 10 to the 4th r (H-squared), in kilometers. This, combined with current theories as well as photochemistry, is consistent with production by simple photodissociation of HCN. The rather random variation of the radial scale length for the apparent decay of CN is indicative not of a true decay scale length, but of the fact that no steady state in the CN parent production rate is achieved for the time scale necessary to build up the observed profile. A revision of the average CN production law with heliocentric distance from published photometry indicates an r(H to the -2nd) law for comet West out to at least 2.555 AU. This implies that the vaporization of this comet was controlled by some species more volatile than water. Based on this and other evidence, CO2 is suggested, but even more volatile molecules like CO cannot be ruled out. Publication: The Astrophysical Journal Pub Date: April 1980 DOI: 10.1086/157910 Bibcode: 1980ApJ...237..641C Keywords: Astronomical Spectroscopy; Comets; Cyanogen; Atmospheric Composition; Brightness; Emission Spectra; Photodissociation; Radiative Transfer; Spectrograms; Spectrum Analysis; Vaporizing; COMETS; ATMOSPHERE; CYANIDE; SPECTROGRAMS; BENNET COMET; WEST COMET; ANALYSIS; PHOTOCHEMISTRY; PHOTODISSOCIATION; DECAY; PHOTOMETRY; VAPORIZATION; RADIATIVE TRANSFER; OBSERVATIONS; DISTANCE; SPECTRUM; PRODUCTION RATES; BRIGHTNESS; CARBON DIOXIDE; ICE; Astrophysics; Comets full text sources ADS |