Title: Giants with infrared excess
Authors: Plets, H
Waelkens, Christoffel
Oudmaijer, RD
Waters, Laurentius
Issue Date: Jul-1997
Publisher: Springer verlag
Series Title: Astronomy and astrophysics vol:323 issue:2 pages:513-523
Abstract: We have correlated optical and infrared catalogs in order to extract a large sample of luminosity class III stars with known infrared flux densities. For a non-negligible fraction of G and K giants, a far-infrared excess emission was found, starting beyond 25 mu m. An explanation in terms of present-day mass loss thus becomes unlikely, since the dust should then be warmer and the excess emission less far in the infrared. We believe that the far-infrared excesses of these objects, most likely first-ascent giants, are related to the Vega phenomenon. The dusty disks around these stars, gradually cooled down during their main-sequence phase, could be reheated once the star leaves the main sequence and enters the luminous post-main-sequence phase. The fairly large sample we constructed enables us to derive an estimation for the occurrence of excesses. This fraction of G or K giants with far-infrared excess appears to be distinctly smaller than among main-sequence stars. Since the higher radiation field of giants could lead to a larger evaporation rate of the circumstellar debris, this fact does not conflict with our hypothesis.
ISSN: 0004-6361
Publication status: published
KU Leuven publication type: DI
Appears in Collections:Institute of Astronomy

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