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DETERMINATION OF THE C 2 PRODUCTION RATE FOR SELECTED COMET FROM VISUAL OBSERVATIONS. Galin Borisov Institute of Astronomy, Bulgarian Academy of Sciences, E-mail: gborisov@astro.bas.bg. Introduction. Comets: C/1996 B2 (Hyakutake) C/1999 S4 (LINEAR) 153P/C1 (Ikeya-Zhang)
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DETERMINATION OF THE C2 PRODUCTION RATE FOR SELECTED COMET FROM VISUAL OBSERVATIONS Galin Borisov Institute of Astronomy, Bulgarian Academy of Sciences, E-mail: gborisov@astro.bas.bg
Introduction • Comets: • C/1996 B2 (Hyakutake) • C/1999 S4 (LINEAR) • 153P/C1 (Ikeya-Zhang) • C/2001 A2 (LINEAR) • C/2000 WM1 (LINEAR) • Visual Observations – ICQ format British Astronomical Association – Comet Section (http://www.ast.cam.ac.uk/~jds/)
Theoretical Background • Transformation from the Comet Visual Magnitude mc to Total Number of C2 Molecules mc – visual magnitude of comet mlx – 1Lx in magnitudes = -13.78 fc2 – oscillation force for Swan band (A3Pg – C3Pu) = 0.031 After replacing known quantities Churumov, K. 1980
Theoretical Background • But this formalism gives “artificial” molecules when the comet is far away from the Sun (more than 1.5 AU) • The solution of this problem is extrapolating these distant “artificial” molecules to small heliocentric distances and subtracting them as a continuum • This idea will be presented in the next section for the fifth selected comets
Theoretical Background • Transformation from Total Number of C2 molecules N to production rate QC2 N –total number of C2 molecules tC2 – lifetime of C2 molecule In literature the lifetime of C2 molecules is given for 1AU and should be correct for heliocentric distance dependence A’Hearn, M. et al. 1995
Conclusions • When using this formalism for converting the visual magnitudes to the total number of C2 molecules we should subtract “artificial” molecules as a continuum • The visual comet magnitude estimated by amateur astronomers can be used for obtaining the C2 production rate for long range of heliocentric distances
References • A’Hearn, M., Osip, D. & Birch, P., 1995, Icarus118, 223-270 • Churyumov, K., 1980, Nauka Moskva • Farnham, T., Schleicher, D., Woodney, L., Birch, P., Eberhardy, C. & Levy, L., 2001, Science292, 1348-1353 • Hicks, M. & Fink, U., 1997, Icarus127, 301-318 • Kiselev, N. & Velichko, F., 1998, Icarus133, 286-292 • Sanwal, B., Kumer, B. & Singh, M., 2002, Bull. Astr. Soc. India, in press