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Multiwavelength observations of the young massive cluster Westerlund 1 have revealed evidence for a large number of OB supergiant and Wolf-Rayet binaries. However, in most cases these findings are based on secondary binary characteristics…
We find that $\sim 15-20$ per cent of A-type stars or red giants are bound with a massive companion ($M_{\rm secondary} > 1M_{\odot}$) in an intermediate wide orbit ($0.5<P<5000\mbox{ yr}$). These massive binaries are expected to form…
Infrared studies have revealed debris likely related to planet formation in orbit around ~30% of youthful, intermediate mass, main sequence stars. We present evidence, based on atmospheric pollution by various elements heavier than helium,…
An accident of misidentification has brought to light the interesting system HD 191588, a new RS CVn-type spectroscopic binary. A radial-velocity study of the primary star, the only seen component, carried out at the Observatoire de…
Thirteen spectroscopic orbits of late-type stars are determined from the high-resolution spectra taken with the CHIRON echelle spectrometer at the 1.5-m CTIO telescope. Most (HIP 14194B, 40523A, 41171A, 51578A, 57572B, 59426A, 62852B,…
A sample of contact binaries discovered by the OGLE project in Baade's Window, with orbital periods longer than one day and with available color and light-curve data, has been analyzed. It consists of only 32 systems, in contrast to 388…
The Tarleton Observatory's 0.8m telescope and CCD photometer were used to obtain 1298 observations of the short period eclipsing binary star MW And. The observations were obtained in Johnson's BVR filters. The light curves show that MW And…
Here we confirm Melnick 34, an X-ray bright star in the 30 Doradus region of the Large Magellanic Cloud, as an SB2 binary comprising WN5h+WN5h components. We present orbital solutions using 26 epochs of VLT/UVES spectra and 22 epochs of…
We show how the recent discovery of a likely close white dwarf companion to the well known star Regulus, one of the brightest stars in the sky, leads to considerable insight into the prior evolutionary history of this star, including the…
We combine different methods to investigate the rotation, determine the shape and estimate the density of near-Earth asteroid (153201) 2000 WO$_{107}$. We carried out photometric observations of the asteroid during the 2020 apparition. Then…
Despite much theoretical and observational progress, there is no known firm upper limit to the masses of stars. Our understanding of the interplay between the immense radiation pressure produced by massive stars in formation and the opacity…
The bright star delta Sco has been considered a typical B0-type object for many years. Spectra of the star published prior to 1990 showed no evidence of emission, but only of short-term line profile variations attributed to nonradial…
PSR J1802-2124 is a 12.6-ms pulsar in a 16.8-hour binary orbit with a relatively massive white dwarf (WD) companion. These properties make it a member of the intermediate-mass class of binary pulsar (IMBP) systems. We have been timing this…
We present an in-depth photometric and spectroscopic study of the contact binary KIC 7766185. Spectroscopic observations were conducted on the Mayall 4-m telescope at Kitt Peak National Observatory and used to extract radial velocities.…
We present the orbital solutions for four OB spectroscopic binaries, MT145, GSC 03161-00815, 2MASS J20294666+4105083, and Schulte 73, and the partial orbital solution to the B spectroscopic binary, MT372, as part of an ongoing study to…
We present the results from the spectroscopic follow-up of WR140 (WC7 + O4-5) during its last periastron passage in January 2009. This object is known as the archetype of colliding wind binaries and has a relatively large period (~ 8 years)…
A 30-day contiguous photometric run with the MOST satellite on the WN5-6b star WR 110 (HD 165688) reveals a fundamental periodicity of P = 4.08 +/- 0.55 days along with a number of harmonics at periods P/n, with n ~ 2,3,4,5 and 6, and a few…
CW Eri is a detached eclipsing binary system of two F-type stars with an orbital period of 2.728 d. Light curves from two sectors of observations with the Transiting Exoplanet Survey Satellite (TESS) and previously published radial velocity…
We present the first near-infrared images of dusty Wolf-Rayet star WR 98a. Aperture masking interferometry has been utilized to recover images at the diffraction-limit of the Keck-I telescope, ~<50 mas at 2.2 micron. Multi-epoch…
Recently, Norton et al. 2002, on the basis of multiwavelength photometry of 1WGA J1958.2+3232, argued that the -1 day alias of the strongest peak in the power spectrum is the true orbital period of the system, casting doubts on the period…