we propose to study the winds of massive stars in the high mass-loss phase of their evolution, i.e. in stages from o- to a-supergiants. the intention is to use the unique spectroscopic and photometric capability of iso to measure accurate strengths and profiles of h and he lines formed in stellar winds, and the ir-continuum which is also formed in the wind. by means of detailed nlte radiative transfer and line formation techniques it will be possible to determine rates of mass-loss and stratification of wind velocity fields much more precisely than hitherto possible. (the present best estimates of the mass loss rates of a and b-stars have an uncertainty of one order of magnitude the results of this study will have important repercussions for our understanding of massive star evolution. they will also provide a crucial test for the theory of radiation driven winds, which is normally applied to predict stellar wind properties as function of stellar parameters. last but not least, the results will be used to calibrate the wind momentum-luminosity relation of blue supergiants which has been found very recently and which has great potential for extragalactic distance determinations.
Instrument
PHT22 , PHT40 , SWS01 , SWS02 , SWS06
Temporal Coverage
1996-03-30T06:16:18Z/1997-03-22T07:35:37Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, Lamers et al., 1999, 'THE WINDS OF EARLY TYPE SUPERGIANTS THE CRITICAL MASS LOSS PHASE OF MASSIVE STARS.', 1.0, European Space Agency, https://doi.org/10.5270/esa-85i6cnr
