Spectrum of comet C/2009 P1 (Garradd) in the optical wavelength range

Abstract

Moderate-resolution spectra of comet C/2009 P1 (Garradd) in the wavelength range from 380 to 540 nm have been analyzed. The spectra were acquired, when the comet was at the distances 1.96 and 1.36 AU from the Sun and the Earth, respectively. The observations were fulfilled in the prime focus of the 6-m BTA telescope (Special Astrophysical Observatory, Russian Academy of Sciences) with the use of the SCORPIO focal reducer. Molecular emissions of C2, C3, CN, CN2, CH, CH+, and CO+ in the cometary coma were identified. In total, 148 emission features were detected. The gas production rate of molecules was determined with the Haser model. The ratios of the gas production rates are log[Q(C2/Q(CN)] = 0.26 and log[Q(C3/Q(CN)] = −1.09. The gas production rates of C2 and C3 molecules are 4.84 × 1026 and 2.16 × 1025 mol/s, respectively.