The following document lists the file abstract/PLAMY_COMETNU3.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
Compared to short-period comets for which we submitted a similar program to observe their nucleus, a new comet will have retain even more pristine clues of the processes which took place during the formation of the Solar System. It is possible that a new bright comet will be observable during the time of ISO observations. We propose to study the nucleus of such a new comet by measuring its thermal emission in the 8-15 micron spectral band as a function of time over approximately 15 hours i.e., the longest period of time during a single orbit. As demonstrated by ground-based observations under favorable conditions of a few comets devoid of coma (e.g., comet P/Arend-Rigaux), the thermal light curve allows to determine, under minimal assumptions, the size and shape of the nucleus and to study its rotational properties. Compared to our program concerning short-period comets, we propose here an independent determination of the surface temperature by using 4 narrow- band filters as made possible by the expected large flux of the nucleus. We shall also observe, as a "by-product", the thermal emission from the innermost dust coma and shall study possible dust structures and follow their temporal evolution.