منابع مشابه
Abundances of cool supergiants in the SMC young cluster NGC 330 ?
NGC 330 is the brightest SMC young cluster and contains many bright supergiants. This cluster has aroused special interest, since the earlier abundance determinations indicated an abundance lower by a factor ∼5 than in the SMC field young population. Taking advantage of our previous high resolution analysis of a sample of type K supergiants in the SMC field (Paper I and II), we analyse 6 cool s...
متن کاملCarbon , 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 ...
متن کاملDIFFERENTIAL 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...
متن کاملThorium abundances on the lunar surface
Measurements of absolute thorium abundances on the lunar surface are presented using both the highand low-altitude data taken with the Lunar Prospector Gamma-Ray Spectrometer. An analysis of the uncertainties shows that the measured uncertainties are < 0.5 μg/g and are close to the theoretical limit of Poisson statistics. Currently, the overall systematic uncertainties are likely dominated by v...
متن کاملEvolution and surface abundances of red giants experiencing deep mixing
We have calculated the evolution of low metallicity red giant stars under the assumption of deep mixing between the convective envelope and the hydrogen burning shell. We find that the extent of the observed abundance anomalies, and in particular the universal O-Na anticorrelation, can be totally explained by mixing which does not lead to significant helium enrichment of the envelope. On the ot...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2016
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201628288