Spectrum of the Short-Period Comet 2P/Encke in the Apparition of 2003

Abstract

Spectra of comet 2P/Encke obtained on November 15 and 22, 2003, in wavelength ranges of λ = 410–580 and 560–720 nm with the Universal Astronomical Grating Spectrograph (UAGS) mounted at the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences is analyzed. The spectral resolution is 0.5 nm. In the cometary coma, the emission bands of C2, CN, CH, and NH2 molecules were detected. The normalized spectral gradient of the reflectivity is (11.95 ± 3.45) and (7.90 ± 2.81)% per 100 nm in wavelength bands of 450–567 and 565–676 nm, respectively. The values of the parameter Afρ are (77 ± 9), (81 ± 9), and (79 ± 9) cm for the BC, GC, and RC continuum filters, respectively, which is indicative of a very low dust content in comet Encke. With the Haser model, we determined the production rate of gas molecules at (1.12 × 1025) and (3.82 × 1024) mol/s for C2 (Δν = 0) and NH2 (0,10,0) molecules, respectively.