dc.contributor.author |
Cui, W. Y |
|
dc.contributor.author |
Sivarani, T |
|
dc.contributor.author |
Christlieb, N |
|
dc.date.accessioned |
2013-10-10T14:08:50Z |
|
dc.date.available |
2013-10-10T14:08:50Z |
|
dc.date.issued |
2013-10 |
|
dc.identifier.citation |
Astronomy and Astrophysics, Vol. 558, A36 |
en |
dc.identifier.issn |
0004-6361 |
|
dc.identifier.uri |
http://hdl.handle.net/2248/6404 |
|
dc.description |
Open Access |
en |
dc.description.abstract |
Aims. The aim of this study is a detailed abundance analysis of the newly discovered r-rich star HE 1405−0822, which has [Fe/H] = −2.40. This star shows enhancements of both r- and s-elements, [Ba/Fe] = + 1.95 and [Eu/Fe] = 1.54, for which reason it is called r+s star. Methods. Stellar parameters and element abundances were determined by analyzing high-quality VLT/UVES spectra. We used Fe I line excitation equilibria to derive the effective temperature. The surface gravity was calculated from the Fe i/Fe ii and Ti i/Ti ii equilibria.
Results. We determined accurate abundances for 39 elements, including 19 neutron-capture elements. HE 1405−0822 is a red giant. Its strong enhancements of C, N, and s-elements are the consequence of enrichment by a former AGB companion with an initial mass of less than 3 M⊙. The heavy n-capture element abundances (including Eu, Yb, and Hf) seen in HE 1405−0822 do not agree with the r-process pattern seen in strongly r-process-enhanced stars. We discuss possible enrichment scenarios for this star. The enhanced α elements can be explained as the result of enrichment by supernovae of type II. Na and Mg may have partly been synthesized in a former AGB companion, when the primary 22Ne acted as a neutron poison in the 13C-pocket |
en |
dc.language.iso |
en |
en |
dc.publisher |
EDP Sciences |
en |
dc.relation.uri |
http://dx.doi.org/10.1051/0004-6361/201321597 |
en |
dc.relation.uri |
http://arxiv.org/abs/1308.4492 |
en |
dc.rights |
© ESO |
en |
dc.subject |
Stars: abundances |
en |
dc.subject |
Stars: AGB and post-AGB |
en |
dc.subject |
Stars: atmospheres |
en |
dc.subject |
Stars: chemically peculiar |
en |
dc.title |
The Hamburg/ESO R-process Enhanced Star survey (HERES) VIII. The r+s star HE 1405 0822 |
en |
dc.type |
Article |
en |