http://arxiv.org/abs/1412.7596
The elemental abundances of symbiotic giants are essential to address the role of chemical composition in the evolution of symbiotic binaries, to map their parent population, and to trace their mass transfer history. However,the number of symbiotic giants with fairly well determined photospheric composition is still insufficient for statistical analyses. This is the third in a series of papers on the chemical composition of symbiotic giants determined from high resolution (R 50000), near-IR spectra. We present results here for the giant star in the V694 Mon, CD-36 8436, WRAY 16-202, Hen 3-1213, V455 Sco, and Hen 2-247 systems. Spectrum synthesis employing standard local thermal equilibrium (LTE) analysis and atmosphere models were used to obtain photospheric abundances of CNO and elements around the iron peak (Sc, Ti, Fe, and Ni). Our analysis reveals metallicities from slightly super-solar for V455 Sco ([Fe/H] +0.3 dex), near solar for WRAY 16-202 and Hen 2-247, slightly sub-solar for V694 Mon and CD-36 8436 ([Fe/H] -0.4 dex), and significantly sub-solar for Hen 3-1213 ([Fe/H] -0.8 dex). The enrichment in 14N isotope, found in all these objects, indicates that the giants have experienced the first dredge-up. For three giants, V694 Mon, CD-36 8436, and WRAY 16-202, this was confirmed by the low 12C/13C isotopic ratios, 24, 8, and 11 respectively. We found that the relative abundance of [Ti/Fe] is large in all the objects studied so far. This appears to be an intrinsic characteristic of all symbiotic giants.
C. Galan, J. Mikolajewska and K. Hinkle
Thu, 25 Dec 14
28/29
Comments: submitted to MNRAS. arXiv admin note: substantial text overlap with arXiv:1410.2760
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