Oxygen Abundances in Late-B through F Supergiants

Carbon , nitrogen , oxygen and lithium abundances of six cool supergiants in the SMC ?

Carbon, nitrogen and oxygen abundances were derived from high-resolution spectra of 6 cool supergiants of the Small Magellanic Cloud. Oxygen-to-iron ratios (mean value [O/Fe] ≈–0.18 dex) are found to be similar to those found in young objects in the LMC and the Galaxy. This result is discussed in terms of chemical evolution. A mean deficiency of the carbon-to-iron ratio of [C/Fe] ≈–0.3 dex and ...

DIFFERENTIAL O AND Si ABUNDANCES IN M 33 EARLY B SUPERGIANTS

We present non-LTE analyses of four M33 early B-supergiant stars and five Galactic counterparts. This is the first time that B supergiants beyond the Magellanic Clouds are analyzed by means of detailed Non-LTE techniques. Among the M33 stars, new spectroscopic observations of B38 (ob21–108) are presented and the object is classified as B1Ia. The classification of another M33 star, B133, is chan...

Neon abundances in normal late - B and mercury - manganese stars

We make new Non-LTE calculations to deduce abundances of neon from visible-regionéchelle spectra of selected Ne i lines in 7 normal stars and 20 HgMn stars. We find that the best strong blend-free Ne line which can be used at the lower end of the T eff range is λ6402, although several other potentially useful Ne i lines are found in the red region of the spectra of these stars. The mean neon ab...

Oxygen line formation in late - F through early - K disk / halo stars ⋆

Properties of Galactic B Supergiants

Physical and wind properties of Galactic B supergiants are presented based upon non-LTE line blanketed model atmospheres, including Sher 25 toward the NGC 3603 cluster. We compare Hα derived wind densities with recent results for SMC B supergiants and generally confirm theoretical expectations for stronger winds amongst Galactic supergiants. Mid B supergiant winds are substantially weaker than ...