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Astron. Astrophys. 326, 1268-1276 (1997)

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Rotation of comet 46P/Wirtanen

K.J. Meech 1, J.M. Bauer 1 and O.R. Hainaut 1, 2

1 Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
2 European Southern Observatory, Casilla 19001, Santiago, Chile

Received 14 March 1997 / Accepted 23 May 1997


We have observed comet 46P/Wirtanen during 1996 June, August and November using the University of Hawai'i 2.2m telescope. At the time of the observations, the comet was at heliocentric distances, r = 2.99, 2.53 and 1.83 AU. During the August run observations were made in order to search for light curve variations due to rotational modulation of the nucleus. The comet was active for all runs, and during 1996 August the coma extended [FORMULA] 16 [FORMULA] (1.8 [FORMULA] 104 km at the distance of the comet) at [FORMULA], and during 1996 November the coma extended [FORMULA] 20 [FORMULA] (2.5 [FORMULA] 104 km at the distance of the comet) at [FORMULA]. The surface brightness profile exhibited a gradient slope of -1.6 and -1.4 in August and November, respectively, only slightly steeper than that expected by radiation pressure and phase angle effects alone. Using a phase-dispersion minimization technique, we find a possible rotation period near 7.6 hours. The color of the nucleus plus dust is [FORMULA], [FORMULA] and [FORMULA] averaged over the three runs.

Key words: comets: 46P/Wirtanen – space vehicles

Send offprint requests to: K.J. Meech, IfA, Hawai'i


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© European Southern Observatory (ESO) 1997

Online publication: April 8, 1998