High resolution spectroscopy of the galactic candidate LBV MWC 314

The results of high-resolution optical spectroscopy obtained for a recently suggested LBV candidate, MWC 314, are presented. Photospheric lines mostly of N ii and S ii have been found for the first time with a resolution of 0.4 - 0.8 Angstroms. They imply a N/O overabundance previously reported for AG and HR Car since no O ii absorptions were detected. Nearly 400 emission lines have been identified in the spectrum between 4190 and 8864 Angstroms many of which appear double-peaked. No significant P Cyg-type absorption components have been found for the optically thick Balmer lines. This suggests that the stellar wind of MWC 314 is non-spherical and the circumstellar envelope is viewed not edge-on. The systemic velocity measured using the emission lines of ionized metals turned out to be +55 km s(-1) , which corresponds to a distance towards the object of 3.0 +/- 0.2 kpc, according to the galactic rotation curve. Our analysis of the characteristics of both photospheric and wind lines resulted in an estimate of the object's T_eff of nearly 25000 K, which, however, needs further improvement. The other stellar parameters were found to be as follows: log L_bol / Lsun = 6.1 +/- 0.3, R_* = 60(+30}_{-10) \ Rsun. Our study confirms that MWC 314 is one of the most luminous stars in the Milky Way. Tables 1--4 are available in electronic form at the CDS via anonymous ftp 130.79.128.5