Loading...
Please wait, while we are loading the content...
Chemical abundance analysis of 19 barium stars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Yang, G. C. Liang, Yeong Cherng Spite, Monique Chen, Yu Qing Zhao, Gang Zhang, B. W. Liu, Guo Qin Liu, Y. Jane Liu, Ning Deng, L. C. Spite, François Hill, Vanessa Zhang, Christiana Xin |
| Abstract | We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures T eff , surface gravities log g, metallicity [Fe/H] and microturbulent velocity ξ t) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α-and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe]>0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe]<0.54. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/1602.08704.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Academy Atmospheric model Barium Classification Compaq LTE Dietary Iron Ehrlich units per deciliter Force of Gravity Gigantism Image resolution Lactic acid Linear algebra Neutrons Science Signal-to-noise ratio Stars, Celestial Stellar (payment network) UVW mapping Velocity (software development) |
| Content Type | Text |
| Resource Type | Article |
