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Optical interferometry of 6 O-type HD stars
We present interferometric observations of six O-type stars that were made with the Precision Astronomical Visible Observations beam combiner at the Center for High Angular... -
Three O-type binaries photometry in LMC
This is the second paper in a series devoted to the study of massive binary systems in the Large Magellanic Cloud (LMC). We mainly aim to provide accurate data that constrains... -
Massive binaries in the LMC
The stellar mass-luminosity relation is poorly constrained by observations for high-mass stars. We describe our program to find eclipsing massive binaries in the Magellanic... -
On the multiplicity of the O star Herschel 36
We present the analysis of high-resolution optical spectroscopic observations of the zero-age main-sequence O star Herschel 36 spanning six years. This star is definitely a... -
Spectroscopic study of Of^+^ supergiants
The transition from early Of stars to WN-type objects is poorly understood. O-type supergiants with emission lines (OIf^+^) are considered to be intermediate between these two... -
Warped disks of YSOs in Galactic center
The central parsec around the supermassive black hole in the Galactic center (GC) hosts more than 100 young and massive stars. Outside the central cusp (R~1") the majority of... -
Radial velocities in the Cas OB6 association
We present the results of time-resolved spectroscopy of 13 O-type stars in the Cas OB6 stellar association. We conducted a survey for radial velocity variability in search of... -
AE Aur and iota Ori runaway stars RV curves
We present the results of our spectroscopic monitoring observations of the late O-type runaway stars AE Aur and iota Ori, carried out between September 2016 and May 2018 using... -
O, B-type & red supergiant masses and luminosities
Massive stars are of interest as progenitors of supernovae, i.e. neutron stars and black holes, which can be sources of gravitational waves. Recent population synthesis models... -
Stellar content of NGC 346
Using CCD UBV photometry and spectroscopy, we have investigated the stellar content of NGC 346, the brightest H II region in the SMC. Spectra of 42 stars confirm that 33 are of... -
IGRINS & Gaia; star formation in Monoceros OB1 & R1
Stellar kinematics provides the key to understanding the star formation process. In this respect, we present a kinematic study of the Monoceros OB1 (Mon OB1) and R1 (Mon R1)... -
Spectral classification of O Vz stars from GOSSS
On the basis of the Galactic O Star Spectroscopic Survey (GOSSS), we present a detailed systematic investigation of the O Vz stars. The currently used spectral classification... -
Massive binary stars from an HST/FGS survey
We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars.... -
Rotational velocities of O stars in clusters
We present the results of a study aimed at assessing whether low and high-mass stars form similarly. Our approach is (1) to examine the observed projected rotational velocities... -
10 Lac UV spectral atlas
Observations of the narrow-lined O-type star 10 Lacertae taken with the Goddard High Resolution Spectrograph in 1992 November are presented. The spectra cover the wavelength... -
Triple star delta Ori radial velocities
Delta Orionis is the closest massive multiple stellar system and one of the brightest members of the Orion OB association. The primary (Aa1) is a unique evolved O star. In this... -
Binarity in fast-rotating O-type stars
The empirical distribution of projected rotational velocities (vsini) in massive O-type stars is characterized by a dominant slow velocity component and a tail of fast rotators.... -
Rotational properties of Galactic O-type stars
Stellar rotation is of key importance for the formation process, evolution, and final fate of massive stars. Performing a reassessment of the empirical rotational properties of... -
Gaia distances to the Carina Nebula Complex
The Carina Nebula Complex (CNC) is one of the most massive and active star forming regions in our Galaxy and contains several large young star clusters. The distances of the... -
CHIPS II. O stars in Trumpler 14 CHIPS-Tr14
Most massive stars belong to multiple systems, yet the formation process leading to such high multiplicity remain insufficiently understood. To help constrain the different...