Dergi makalesi Açık Erişim

Low mass stellar companions around four giant stars

2015    Yilmaz, M.; Bikmaev, I.; Sato, B.; Selam, S. O.; Galeev, A. I.; Keskin, V.; Izumiura, H.; Irtuganov, E. N.; Kambe, E.; Ozavci, I.; Melnikov, S. S.; Zhuchkov, R. Ya.; Okada, N.

We present three low-mass and one solar mass companions found around four intermediate-mass giants HD1695, HD120235, HD145316 and HD200004 from precise radial velocity measurements using the 1.5 m Russian-Turkish Telescope (RTF150) at the TUBITAK National Observatory of Turkey (TUG). The stellar parameters, which are effective temperature (T-eff), surface gravity (logg) and metallicity ([Fe/H]), as well as rotational velocity (vsini) are obtained from spectral analysis. From the estimated stellar masses, the orbital parameters of the companions are also derived. We find two types of Keplerian solutions for the companion of HD120235: (1) periods 5522 days and eccentricity of e similar to 0.93, and (2) periods 1566 days and eccentricity of e similar to 0.83. From the abundances analysis HD1695 is found to be a metal-rich star with [Fe/H] > 0.1, while HD200004 is a metal poor star with [Fe/H] < -0.2. The other two stars, HD120235 and HD145316, have solar-like abundances with [Fe/H] similar to 0.0. Our stellar parameters and orbital solutions show that all of these stars are evolved intermediate-mass giants. (C) 2014 Elsevier B.V. All rights reserved.