Contents of: VI/111/./abstract/DHUTSEME_LBVMC.abs

The following document lists the file abstract/DHUTSEME_LBVMC.abs from catalogue VI/111.
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 Luminous Blue Variable stars (LBVs) are extreme supergiants
 generally thought to represent a short-lived intermediate
 stage between O and WR stars.  About ten LBVs are presently
 known in our Galaxy.  Most of them are surrounded by a dusty
 nebula apparently constituted of nuclear processed material
 ejected by the star.  The nebulae were detected by IRAS,
 allowing the evaluation of the dust mass in the nebula which
 was found to correlate with the central star luminosity, as do
 the ionized gas mass.  Such a "nebular dust mass - stellar
 luminosity" relation constitutes an important constraint for
 understanding the mass-loss mechanisms, and for distinguishing
 between the various instability models.  Most of these
 mechanisms depend on metallicity.
 It is therefore particularly interesting to study the
 properties of these objects, and especially their dusty
 nebulae, in other galaxies with namely different
 metallicities.  Here, using the better sensivity provided by
 ISO, we propose to study the dust properties of luminous
 early-type stars (LBVs and the related Of/WN stars) in the
 Magellanic Clouds with the following questions in mind:  Are
 the extragalactic LBVs also associated with dusty nebulae?
 In which proportion?  Have the Of/WN stars similar dust
 properties?  Does a "nebular mass - stellar luminosity"
 relation also exist?  Is it quantitatively different from the
 galactic one?  Does it depend on metallicity?  Is the
 gas-to-dust ratio similar to the ratio found for galactic
 LBV-type nebulae?
 This can be done by measuring the continuum flux with ISOPHOT
 (PHT03) in the 12, 25, 60 and 100 micron IRAS bands.

 %Note added in PDEC:
 %Following the recommandations by OTAC about the feasibility,
 %the measurements at 60 and 100 micron with the P detector
 %in chopped mode (PHT03) will be done with the C detector
 %in raster mode (PHT22, concatenated). 
 
 

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