Post-perihelion observations of comet 1P/Halley. V: r_h = 28.1 AU

O. R. Hainaut (1) , Audrey Delsanti (2, 3) , Karen J. Meech (4) , Richard M. West (5)

1 European Southern Observatory
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 Pôle Planétologie du LESIA
4 Institute for Astronomy, University of Hawaii
5 ESO - European Southern Observatory

Deep CCD observations have been performed simultaneously with the three 8.2 m Very Large Telescopes at Paranal, in the direction of comet 1P/Halley, on March 6-8, 2003. The comet, at heliocentric distance r=28.1 AU, was convincingly detected (at S/N=8) on a composite of 32 284 s exposure, as a point-source located 1.4'' from the expected position. The object is also visible (at the S/N=3-5 level) on independent per-night or per-instrument composites, confirming the reality of the object, and the match of the observed motion over 3 consecutive nights with the predicted motion of 1P/Halley guarantees that this cannot be another Solar System object. The magnitude of the object, R=28.22 ± 0.13, is compatible with the average cross-section of the bare nucleus.

Domaines: Astrophysique [astro-ph]; Planète et Univers [physics]

O. R. Hainaut, Audrey Delsanti, Karen J. Meech, Richard M. West. Post-perihelion observations of comet 1P/Halley. V: r_h = 28.1 AU. Astronomy and Astrophysics - A&A, 2004, 417, pp.1159-1164. ⟨10.1051/0004-6361:20035658⟩. ⟨hal-03796974⟩