Aims. We report new results for the massive evolved and main sequence members of the young galactic cluster DBS2003 179. We determine the physical parameters and investigate the high-mass stellar content of the cluster, as well as of its close vicini
ty. Methods. Our analysis is based on ISAAC/VLT moderate-resolution (Rapprox4000) infrared spectroscopy of the brightest cluster members. We derive stellar parameters for sixteen of the stellar members, using full non-LTE modeling of the obtained spectra. Results. The cluster contains three late WN or WR/LBV stars (Obj 4, Obj 15, and Obj 20:MDM32) and at least 5 OIf and 5 OV stars. According to the Hertzsprung-Russell diagram for DBS2003 179, the WR stars show masses above 85Msun, the OIf stars are between 40 and 80Msun, and the main sequence O stars are >20Msun. There are indications of binarity for Obj 4 and Obj 11, and Obj 3 shows a variable spectrum. The cluster is surrounded by a continuous protostar formation region most probably triggered by DBS2003 179. Conclusions. We confirm that DBS2003 179 is young massive cluster (2.5 10^4Msun) very close to the Galactic center at the distance of 7.9+-0.8 kpc.
We present the results of optical wavelength observations of the unusual SMC eclipsing binary system HD 5980 obtained in 1999 and 2004--2005. Radial velocity curves for the erupting LBV/WR object (star A) and its close WR-like companion (star B) are
obtained by deblending the variable emission-line profiles of N IV and N V lines under the simplistic assumption that these lines originate primarily in the winds of star A and star B. The derived masses M_A=58--79 Mo and M_B=51--67 Mo, are more consistent with the stars location near the top of the HRD than previous estimates. The presence of a wind-wind interaction region is inferred from the orbital phase-dependent behavior of He I P Cygni absorption components. The emission-line intensities continued with the declining trend previously seen in UV spectra. The behavior of the photospheric absorption lines is consistent with the results of Schweickhardt (2002) who concludes that the third object in the combined spectrum, star C, is also a binary system with P(starC)~96.5 days, e=0.83. The data used in this paper will be made publicly available for further analysis.
Young massive clusters are perfect astrophysical laboratories for study of massive stars. Clusters with Wolf-Rayet (WR) stars are of special importance, since this enables us to study a coeval WR population at a uniform metallicity and known age. GLI
MPSE30 (G30) is one of them. The cluster is situated near the Galactic plane (l=298.756deg, b=-0.408deg) and we aimed to determine its physical parameters and to investigate its high-mass stellar content and especially WR stars. Our analysis is based on SOFI/NTT JsHKs imaging and low resolution (R~2000) spectroscopy of the brightest cluster members in the K atmospheric window. For the age determination we applied isochrone fits for MS and Pre-MS stars. We derived stellar parameters of the WR stars candidates using a full nonLTE modeling of the observed spectra. Using a variety of techniques we found that G30 is very young cluster, with age t~4Myr. The cluster is located in Carina spiral arm, it is deeply embedded in dust and suffers reddening of Av~10.5+-1.1mag. The distance to the object is d=7.2+-0.9kpc. The mass of the cluster members down to 2.35Msol is ~1600Msol. Clusters MF for the mass range of 5.6 to 31.6Msol shows a slope of Gamma=-1.01+-0.03. The total mass of the cluster obtained by this MF down to 1Msol is about 3x10^3Msol. The spectral analysis and the models allow us to conclude that in G30 are at least one Ofpe/WN and two WR stars. The WR stars are of WN6-7 hydrogen rich type with progenitor masses more than 60Msol. G30 is a new member of the exquisite family of young Galactic clusters, hosting WR stars. It is a factor of two to three less massive than some of the youngest super-massive star clusters like Arches, Quintuplet and Central cluster and is their smaller analog.
