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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: [email protected]. Introduction. Comets: C/1996 B2 (Hyakutake) C/1999 S4 (LINEAR) 153P/C1 (Ikeya-Zhang) - PowerPoint PPT Presentation
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DETERMINATION OF THE CDETERMINATION OF THE C22
PRODUCTION RATE FOR PRODUCTION RATE FOR SELECTED COMET FROM SELECTED COMET FROM VISUAL OBSERVATIONSVISUAL OBSERVATIONS
Galin Borisov
Institute of Astronomy, Bulgarian Academy of Sciences,
E-mail: [email protected]
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 (3g – 3u) = 0.031
After replacingknown quantities
Churumov, K. 1980
2
38
22)(4.0
1037.1
10
C
mm
f
rN
lxc
40
22)78.13(4.0
1025.4
10
r
Ncm
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 moleculesC2 – lifetime of C2 molecule
In literature the lifetime of C2 molecules is given for 1AUand should be correct forheliocentric distance dependence
A’Hearn, M. et al. 1995
2
2
CC
NQ
2
41,
2
2sec106.6
rC
AUC
C/1996 B2 (Hyakutake)
C/1996 B2 (Hyakutake)
C/1996 B2 (Hyakutake)
C/1996 B2 (Hyakutake)
C/1999 S4 (LINEAR)
C/1999 S4 (LINEAR)
C/1999 S4 (LINEAR)
C/1999 S4 (LINEAR)
153P/C1 (Ikeya-Zhang)
153P/C1 (Ikeya-Zhang)
153P/C1 (Ikeya-Zhang)
153P/C1 (Ikeya-Zhang)
C/2001 A2 (LINEAR)
C/2001 A2 (LINEAR)
C/2001 A2 (LINEAR)
C/2001 A2 (LINEAR)
C/2000 WM1 (LINEAR)
C/2000 WM1 (LINEAR)
C/2000 WM1 (LINEAR)
C/2000 WM1 (LINEAR)
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, Icarus 118, 223-270
Churyumov, K., 1980, Nauka Moskva Farnham, T., Schleicher, D., Woodney, L., Birch, P.,
Eberhardy, C. & Levy, L., 2001, Science 292, 1348-1353
Hicks, M. & Fink, U., 1997, Icarus 127, 301-318
Kiselev, N. & Velichko, F., 1998, Icarus 133, 286-292 Sanwal, B., Kumer, B. & Singh, M., 2002, Bull. Astr. Soc.
India, in press