Related papers: A VLT/FLAMES survey for massive binaries in Wester…

The star NGC 3603-A1 has long been known to be a very massive binary, consisting of a pair of O2-3If*/WN5-6 stars, which show Wolf-Rayet-like emission due to their luminosities being near the Eddington limit. The system has been poorly…

Context. Massive-binary evolution models predict that some systems will go through an evolutionary phase where the original primary has become a supernova and left a compact object behind that then orbits a Wolf-Rayet (hereafter, WR) star.…

We present a spectral analysis of four LMC WC-type Wolf-Rayet (WR) stars (BAT99-8, BAT99-9, BAT99-11, and BAT99-52) to shed light on two evolutionary questions surrounding massive stars. The first is: are WO-type WR stars more oxygen…

The hot star HDE 326823 is a candidate transition-phase object that is evolving into a nitrogen-enriched Wolf-Rayet star. It is also a known low-amplitude, photometric variable with a 6.123 d period. We present new, high and moderate…

The diverse massive stellar population in the young massive cluster Westerlund 1 (Wd~1) provides an ideal laboratory to observe and constrain mass-loss processes throughout the transitional phase of massive star evolution. A set of high…

BAT99-129 is a rare, short-period eclipsing Wolf-Rayet binary in the Large Magellanic Cloud. We present here medium-resolution NTT/EMMI spectra that allow us to disentangle the spectra of the two components and find the orbital parameters…

We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the fundamental properties of the O-star…

(Abridged) We perform a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of Wolf-Rayet (WR) stars. In this paper we present the analysis of the O and WR star…

We report a single-lined white dwarf-main sequence binary system, LAMOST J172900.17+652952.8, which is discovered by LAMOST's medium resolution time-domain surveys. The radial velocity semi-amplitude and orbital period of the optical…

Accumulating evidence points to a binary nature for the Wolf-Rayet ([WC]) central stars, a group that constitutes about 15% of all central stars of planetary nebula. From ISO observations, a dual dust chemistry (oxygen- and carbon-rich) has…

Because of their large number of stars spread over the entire stellar mass spectrum, starburst clusters are highly suitable to benchmark and calibrate star formation models and theories. Among the handful of Galactic starburst clusters,…

Wolf-Rayet stars are evolved massive stars, and the relative number of WC-type and WN-type WRs should vary with the metallicity of the host galaxy, providing a sensitive test of stellar evolutionary theory. However, past studies of the WR…

Most Wolf-Rayet stars (WR) of WC9 sub-type exhibit a dusty circumstellar envelope, but it is still a matter of debate how dust can form in their harsh environment. In a few cases, a pinwheel-like structure of the dusty envelope has been…

This work provides a statistical analysis of the massive star binary characteristics in the Cygnus OB2 Association using radial velocity information of 114 B3-O3 primary stars and orbital properties for the 24 known binaries. We compare…

Post-common-envelope binaries (PCEBs) containing a white dwarf (WD) and a main-sequence (MS) star can constrain the physics of common envelope evolution and calibrate binary evolution models. Most PCEBs studied to date have short orbital…

While the first binary post-AGB stars were serendipitously discovered, the distinct characteristics of their Spectral Energy Distribution (SED) allowed us to launch a more systematic search for binaries. We selected post-AGB objects which…

We aim at searching for secular evolution of the orbital period in the short-period binary system WR 127 (WN3b+O9.5V, $P = 9.555^d$). We performed new low-resolution spectroscopic observations of WR 127 on 2.5-m CMO SAI telescope to…

We report the discovery of variability in the X-ray emission from the Wolf-Rayet type star WR 65. Using archival Chandra data spanning over 5 yr we detect changes of the X-ray flux by a factor of 3 accompanied by changes in the X-ray…

Only a small number of high mass stars (> 30 Mo) have fundamental parameters (i.e. masses and radii) measured with high enough accuracy from eclipsing binaries to constrain formation and evolutionary models of massive stars. This work aims…

We determine the orbits of four double degenerate systems (DDs), composed of two white dwarfs, and of two white dwarf -- M dwarf binaries. The four DDs, WD1022+050, WD1428+373, WD1824+040, and WD2032+188, show orbital periods of 1.157155(5)…