High-Resolution Spectroscopy of the Hydrogen-Deficient Binary Upsilon Sgr
Abstract
The high resolution spectra of hydrogen-deficient binary Upsilon Sgr are analyzed. The atmospheric parameters are T eff=12300± 200 K, log g=2.5±0.5 and ξ t=5-15 km s-1 depending on the element. For Fe II ξ t=9.3±0.3 km s-1. Iron is slightly underabundant (--0.2 dex). Nitrogen is overabundant with [N/Fe] ≈ 1.0, carbon and oxygen are underabundant with [C/Fe] ≈ --1.6 and [O/Fe] ≈ --1.1. The s-process elements Y, Zr and Ba are overabundant about 0.5 dex. Quite large number of emission lines, both permitted and forbidden, originating from low excitation levels of neutral and ionized metals, are identified. Radial velocities of these emission lines indicate that an accretion disk in the system is present.
- Publication:
-
Baltic Astronomy
- Pub Date:
- 2012
- DOI:
- 10.1515/astro-2017-0382
- Bibcode:
- 2012BaltA..21..219K
- Keywords:
-
- stars: atmospheres;
- stars: individual: Upsilon Sgr