| Description |
we have correlated the bright star (bsc) and michigan spectral catalogs (msc) with the iras catalogs to determine which, if any, luminosity class iii giant stars have associated circumstellar dust particles. of more than 40,000 class iii giant stars in the bsc & msc, we find that perhaps 300 have associated dust and, of these, we have chosen the best 100 for observations at 60 and 100 microns with isophot (although not all are accessible in a given launch window). the presence of substantial dust near these stars, most of which are post-main sequence, first ascent, giants, is not easily explained. most of the stars have apparent iras excesses primarily or exclusively at 60 microns. iso data can be used to separate the wheat from the chaff and show which stars are truly associated with dust and, by measuring the dust temperature, its location relative to the star. then, armed with this clean sample, ground based measurements (e.g., echelle spectroscopy) will, hopefully, reveal common threads among the dusty stars which, in turn, could lead to an understanding of the underlying phenomenon. explanation of the presence of dust orbiting first ascent giants may involve one or more of the following phenomena: mass loss, binarity, planetary systems, evaporation of kuiper-belt material, or ? whereas the presence of particulate material near pre-main sequence and main sequence stars and near agb and supergiant stars may be accounted for in rather straightforward ways, there is no obvious way to produce and retain large amounts of dust near first ascent giant stars. |
