EDP Sciences
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Volume 441, Number 1, October I 2005
Page(s) 303 - 308
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20042417

A&A 441, 303-308 (2005)
DOI: 10.1051/0004-6361:20042417

A detailed spectroscopy of the carbon-rich star BD +57$^{\circ}$ 2161

L. Zacs1, M. R. Schmidt2, F. A. Musaev3, 4, 5, G. A. Galazutdinov6, 3 and J. Sperauskas7

1  Institute of Atomic Physics and Spectroscopy, University of Latvia, Raina bulvaris 19, 1586 Riga, Latvia
    e-mail: zacs@latnet.lv
2  N. Copernicus Astronomical Center, ul. Rabianska 8, 87-100 Torun, Poland
    e-mail: schmidt@ncac.torun.pl
3  Special Astrophysical Observatory and Isaac Newton Institute of Chile, SAO Branch, Nizhnij Arkhyz, 369167, Russia
    e-mail: faig@sao.ru, gala@sao.ru
4  ICAMER, National Academy of Sciences of Ukraine, 361605 Peak Terskol, Kabardino-Balkaria, Russia
5  Shamakhy Astrophysical Observatory, National Academy of Sciences of Azerbaijan, Azerbaijan
6  Korean Astronomy Observatory, Optical Astronomy Division, 61-1, Whaam-Dong, Yuseong-Gu, Daejon, 305-348, Korea
    e-mail: gala@boao.re.kr
7  Vilnius University Observatory, Ciurlionio 29, Vilnius 2009, Lithuania
    e-mail: julius.sperauskas@ff.vu.lt

(Received 23 November 2004 / Accepted 9 May 2005 )

An LTE abundance analysis based on high-resolution spectra is presented for the carbon-rich star BD $+57^{\circ}$ 2161, whose evolutionary status is unknown. With $\rm [C/Fe] =+0.4$ dex and a mean s-process overabundance of $\rm [s/Fe] \simeq +1.5$ dex the peculiar atmospheric composition of BD $+57^{\circ}$ 2161 is confirmed. The 12C/13C abundance ratio was found to be about 10. The mild iron deficiency, $\rm [Fe/H] = -0.2$, supports the idea that BD $+57^{\circ}$ 2161 could be an old-disk-population object. Radial-velocity measurements confirm the binary nature of the star. Therefore the peculiar chemical composition could be due to the mass transfer from the secondary - AGB star in the past. Orbital parameters are estimated for another star of this group, BD $+75^{\circ}$ 348.

Key words: stars: evolution -- stars: atmospheres -- stars: abundances -- stars: chemically peculiar -- stars: individual: BD $+57^{\circ}$ 2161 -- stars: individual: BD $+75^{\circ}$ 348

SIMBAD Objects

© ESO 2005