Related papers: R144 revealed as a double-lined spectroscopic bina…
We analyze extensive BVRI photometry and radial velocity measurements for three double-lined deeply-eclipsing binary stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 d) detached binary V375 Cep is a high…
Eclipsing binaries in star clusters offer more stringent tests of stellar evolution theory than field binaries because models must not only match the binary properties, but also the radiative properties of all other cluster members at a…
We present the results of our study of the luminous (L_{X} ~ 10^{39} erg/s) X-ray binary CXOU J121538.2+361921 in NGC 4214, the high mass X-ray binary with the shortest known orbital period. Using Chandra data, we confirm the ~13,000 s (3.6…
Optical spectroscopy of CPD -59 2635, one of the O-type stars in the open cluster Trumpler 16 in the Carina Nebula, reveals this star to be a double-lined binary system. We have obtained the first radial velocity orbit for this system,…
We report precise Doppler measurements of HD 142022 obtained during the past six years with the CORALIE echelle spectrograph at La Silla Observatory together with a few additional observations made recently with the HARPS echelle…
We describe an astrometric and spectroscopic campaign to confirm the youth and association of a complete sample of candidate wide companions in Taurus and Upper Sco. Our survey found fifteen new binary systems (3 in Taurus and 12 in Upper…
We report the discovery of a relatively bright eclipsing binary system, which consists of a white dwarf and a main sequence K7 star with clear signs of chromospheric and spot activity. The light curve of this system shows $\sim0.2$mag…
Characterizing the local space density of double degenerate binary systems is a complementary approach to broad sky surveys of double degenerates to determine the expected rates of white dwarf binary mergers, in particular those that may…
NGC 7789 is an intermediate-age open cluster with an age that is similar to the mean age of contact binary stars. V12 is a bright UMa-type binary star with an orbital period of 0.397 day. The first complete light curves of V12 in V, R, and…
Very massive stars preferentially reside in the cores of their parent clusters and form binary or multiple systems. We study the role of tight very massive binaries in the origin of the field population of very massive stars. We performed…
Melnick 34 (Mk 34) is one of the most massive binary systems known and is one of the brightest X-ray point sources in the 30 Doradus region. We investigated the impact of this massive system on the surrounding interstellar medium (ISM)…
We report new multi-colour photometry and high-resolution spectroscopic observations of the long-period variable V501 Aur, previously considered to be a weak-lined T-Tauri star belonging to the Taurus-Auriga star-forming region. The…
As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity…
AR Aur is a detached eclipsing binary containing two late-B stars which are chemically peculiar, on a circular orbit of period 4.135 d. The primary is a HgMn star which shows temporal changes in its chemical abundances and spectral line…
New deep, high-resolution H-alpha imagery from the UK Schmidt Telescope (UKST) Unit's H-alpha survey of the Southern Galactic Plane reveals the presence of a faint, highly circular, planetary nebula surrounding a very long period variable…
We present time-series $BVI$ photometry for the Galactic globular cluster NGC 6402 (M14). The data consists of $\sim$137 images per filter, obtained using the 0.9m and 1.0m SMARTS telescopes at the Cerro Tololo Inter-American Observatory.…
I report my discovery of the large-amplitude Algol-type eclipsing binary system which was initially added to the AAVSO International Variable Star Index (VSX) under the designation of Romanov V20. I describe selection criteria for searching…
We present ground-based broad-band photometry of two transits in the WASP-44 planetary system obtained simultaneously through four optical (Sloan g', r', i', z') and three near-infrared (NIR; J, H, K) filters. We achieved low scatters of…
We present the discovery of OB type absorption lines superimposed to the emission line spectrum and the first double-lined orbital elements for the massive Wolf-Rayet binary HDE 318016 (=WR 98), a spectroscopic binary in a circular orbit…
We present here the results of Arecibo timing of PSR B1516+02B, a 7.95-ms pulsar in a binary system with a ~0.17 solar mass companion and an orbital period of 6.85 days located in the globular cluster M5. The eccentricity of the orbit (e =…