Zobrazeno 1 - 10
of 64
pro vyhledávání: '"Behara, N. T."'
Autor:
Kupfer, Thomas, Przybilla, Norbert, Heber, Ulrich, Jeffery, C. Simon, Behara, N. T., Butler, Keith
Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10$
Externí odkaz:
http://arxiv.org/abs/1706.05389
Autor:
Jeffery, C. S., Baran, A. S., Behara, N. T., Kvammen, A., Martin, P., N., Naslim, Østensen, R. H., Preece, H. P., Reed, M. D., Telting, J. H., Woolf, V. M.
UVO0825+15 is a hot bright helium-rich subdwarf which lies in {\it K2} Field 5 and in a sample of intermediate helium-rich subdwarfs observed with {\it Subaru/HDS}. The {\it K2} light curve shows low-amplitude variations, whilst the {\it Subaru} spec
Externí odkaz:
http://arxiv.org/abs/1611.01616
Subluminous B stars come in a variety of flavours including single stars, close and wide binaries, and pulsating and non-pulsating variables. A majority have helium-poor surfaces (helium by number nHe<1%), whilst a minority have extremely helium-rich
Externí odkaz:
http://arxiv.org/abs/1204.4387
Autor:
Bonifacio, P., Sbordone, L., Caffau, E., Ludwig, H. -G., Spite, M., Hernández, J. I. González, Behara, N. T.
Aims: The purpose of our study is to determine the chemical composition of a sample of 16 candidate Extremely Metal-Poor (EMP) dwarf stars, extracted from the Sloan Digital Sky Survey (SDSS). There are two main purposes: in the first place to verify
Externí odkaz:
http://arxiv.org/abs/1204.1641
Helium-rich subdwarf B (He-sdB) stars represent a small group of low-mass hot stars with luminosities greater than those of conventional subdwarf B stars, and effective temperatures lower than those of subdwarf O stars. By measuring their surface che
Externí odkaz:
http://arxiv.org/abs/1010.5146
Publikováno v:
MNRAS, July 2010
The connection between helium-rich hot subdwarfs of spectral types O and B (He-sdB) has been relatively unexplored since the latter were found in significant numbers in the 1980's. In order to explore this connection further, we have analysed the sur
Externí odkaz:
http://arxiv.org/abs/1008.0546
Autor:
Hernandez, J. I. Gonzalez, Bonifacio, P., Ludwig, H. -G., Caffau, E., Behara, N. T., Freytag, B.
The measurement of oxygen lines in metal-poor unevolved stars, in particular near-UV OH lines, can provide invaluable information on the properties of the Early Galaxy. Near-UV OH lines constitute an important tool to derive oxygen abundances in meta
Externí odkaz:
http://arxiv.org/abs/1005.3754
The metal-poor end of the Spite plateau. 1: Stellar parameters, metallicities and lithium abundances
Autor:
Sbordone, L., Bonifacio, P., Caffau, E., Ludwig, H. -G., Behara, N. T., Hernandez, J. I. Gonzalez, Steffen, M., Cayrel, R., Freytag, B., Veer, C. Van't, Molaro, P., Plez, B., Sivarani, T., Spite, M., Spite, F., Beers, T. C., Christlieb, N., Francois, P., Hill, V.
We present VLT-UVES Li abundances for 28 halo dwarf stars between [Fe/H]=-2.5 and -3.5, 10 of which have [Fe/H]<-3. Four different T_eff scales have been used. Direct Infrared Flux Method (IRFM) has been used on the basis of 2MASS infrared photometry
Externí odkaz:
http://arxiv.org/abs/1003.4510
Autor:
Behara, N. T., Bonifacio, P., Ludwig, H. -G., Sbordone, L., Hernández, J. I. González, Caffau, E.
The origin of carbon-enhanced metal-poor stars enriched with both s and r elements is highly debated. Detailed abundances of these types of stars are crucial to understand the nature of their progenitors. The aim of this investigation is to study in
Externí odkaz:
http://arxiv.org/abs/1002.1670
Autor:
Hernandez, J. I. Gonzalez, Bonifacio, P., Caffau, E., Steffen, M., Ludwig, H. -G., Behara, N. T., Sbordone, L., Cayrel, R., Zaggia, S.
Most Globular Clusters are believed to host a single stellar populations. They can thus be considered a good place to study the Spite plateau and probe for possible evolutionary modifications of the Li content. We want to determine the Li content of
Externí odkaz:
http://arxiv.org/abs/0909.0983