SIMBAD references

1997A&A...323..513P - Astronomy and Astrophysics, volume 323, 513-523 (1997/7-2)

Giants with infrared excess.


Abstract (from CDS):

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 25µm. 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.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: evolution - stars: late-type - stars: statistics - infrared: stars

Simbad objects: 115

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