EDP Sciences
Free Access
Issue
A&A
Volume 419, Number 1, May III 2004
Page(s) 375 - 383
Section Planets and planetary systems
DOI https://doi.org/10.1051/0004-6361:20040073


A&A 419, 375-383 (2004)
DOI: 10.1051/0004-6361:20040073

The nuclei of comets 126P/IRAS and 103P/Hartley 2

O. Groussin1, P. Lamy1, L. Jorda1 and I. Toth1, 2

1  Laboratoire d'Astronomie Spatiale, BP 8, 13376 Marseille Cedex 12, France
2  Konkoly Observatory, PO Box 67, Budapest 1525, Hungary

(Received 6 May 2003 / Accepted 15 January 2004 )

Abstract
We report the detection of the nucleus of 126P/IRAS and 103P/Hartley 2 with the Infrared Camera of the Infrared Space Observatory (ISOCAM). 126P/IRAS was observed on 12 November 1996, when it was at $r_{\rm h}=1.71$ AU from the Sun and $\Delta=1.32$ AU from the Earth. 103P/Hartley 2 was observed on 5 February 1998, when it was at $r_{\rm h}=1.21$ AU from the Sun and $\Delta=0.91$ AU from the Earth. The observations were performed with the broadband LW10 filter centered at 11.5  $\mu$m. The spatial resolution was adequate to separate the thermal emission of the nuclei from that of their respective comae. We combined the ISOCAM observations with measured water production rates, using a model that considers a spherical nucleus with a macroscopic mosaic of small and numerous active and inactive regions, and we derived a radius of $1.57\pm0.14$ km and an active fraction at perihelion of $0.11\pm0.03$ for 126P/IRAS, and a radius of $0.71\pm0.13$ km and an active fraction of ~1 at perihelion and $0.30\pm0.11$ at 1.11 AU post-perihelion for 103P/Hartley 2. These two examples illustrate the large diversity of activity pattern that exists among cometary nuclei.


Key words: comets: individual: 126P/IRAS -- comets: individual: 103P/Hartley 2 -- comets: general

Offprint request: O. Groussin, grousssin@astro.umd.edu




© ESO 2004

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.