Astron. Astrophys. 335, L46-L49 (1998)

1. Introduction

Jupiter family comets represent a large group of the short-period comets in the Solar System. As their aphelia lie between 5 AU and 6 AU, they are in principle observable along their entire orbit. Thus, they are excellently suited to serve as targets for a complete description of the physico-chemical evolution of a comet along its orbit. It has been realized over the years that the evolution of the activity of a comet as it moves along its orbit is of the utmost importance to understand the structure and compositon of its nucleus. Now, the European Space Agency is preparing the International Rosetta Mission (ROSETTA ), a rendez-vous mission to Jupiter family comet 46P/Wirtanen (P   5.5 yrs) dedicated to study its nucleus and coma evolution from onset of activity beyond 3 AU through perihelion. This mission will provide an unprecedented, unique data set of in-situ measurements regarding a single comet which will enable us to derive many yet unknown parameters. However, just one single comet will be studied by ROSETTA . It is therefore crucial to be able to establish the proper correlation between the results that will be furnished by the space rendez-vous and the data that can be obtained by remote observations from Earth. We have monitored the evolution of activity of comet 46P/Wirtanen along the same part of the orbit that will be covered by the space mission. These observations provide valuable information on the ROSETTA target comet for the preparation of the mission and are at the same time an important complement to the space mission itself. They will be needed to put the results expected from the ROSETTA Mission into a larger context by establishing a link between the spacecraft data and the information which can be retrieved from remote sensing observations and can then be transferred also to other comets.

© European Southern Observatory (ESO) 1998

Online publication: June 18, 1998
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