Related papers: BG Gem - a Poorly-Studied Binary with a Possible B…

We studied both components of a slightly overlooked visual binary HR 1847 spectroscopically to determine its basic physical and orbital parameters. Basic stellar parameters were determined by comparing synthetic spectra to the observed…

Gamma-ray binaries are stellar systems containing a neutron star or black hole with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our…

We present the first orbital elements for the massive close binary, HD 115071, a double-lined spectroscopic binary in a circular orbit with a period of 2.73135 +/- 0.00003 days. The orbital semiamplitudes indicate a mass ratio of M_2/M_1 =…

We have used NIRSPEC on Keck II to obtain $K$-band spectroscopy of the low mass X-ray binary V616 Mon (= A0620$-$00). V616 Mon is the proto-typical soft x-ray transient containing a black hole primary. As such it is important to constrain…

HD~69479/80 is a composite-spectrum binary whose components are a late-G giant and an early-A dwarf. The orbit has a period of only 91 days (which seems short for a system containing a cool giant with a radius of $\sim$13 solar radii), and…

$\zeta$ Phoenicis is a bright binary system containing B6V and B8V stars. It has deep total and annular eclipses, a slightly eccentric orbit with a period of 1.669 d, apsidal motion and a third body on a wider orbit. The Transiting…

We present photometric observations in B and V as well as spectroscopic observations of the detached, eccentric 6.6-day double-lined eclipsing binary GG Ori, a member of the Orion OB1 association. Absolute dimensions of the components,…

Recent studies have proposed that GRAVITY+ instrument is able to trace the circular orbit of the subparsec close-binary supermassive black holes (CB-SMBHs) by measuring the photocentre variation of the hot dust emission. However, the…

We have monitored the R and I magnitudes of the black hole candidate system A0620-00 (V616 Mon) in the years 1991-95 at the Wise Observatory. Combining our data with some additional measurements, we analyze a sparsely covered 7 years light…

The formation and evolution of binary black holes (BH) is studied using the modern evolutionary scenario for very massive stars with high mass loss (Vanbeveren et al. 1998). Main sequence stars with masses $M>35 M_\odot$ are assumed to form…

Balmer and Paschen continuum emission as well as Balmer series lines of P Cygni-type profile from H_gamma through H_23 are revealed in the violet spectra of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell (`silicate…

In this Letter we explore the hypothesis that the quasar SDSSJ092712.65+294344.0 is hosting a massive black hole binary embedded in a circumbinary disc. The lightest, secondary black hole is active, and gas orbiting around it is responsible…

Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to look for hot binary companions to cool AGB stars…

A dozen short-period detached binaries are known to host transiting circumbinary planets. In all circumbinary systems so far, the planetary and binary orbits are aligned within a couple of degrees. However, the obliquity of the primary…

Up to now, most stellar-mass black holes were discovered in X-ray emitting binaries, in which the black holes are formed through a common-envelope evolu tion. Here we give evidence for the presence of a massive black hole candidate as a…

Recently, several non-interacting black hole-stellar binaries have been identified in Gaia data. For example, Gaia BH1, where a Sun-like star is in a moderate eccentricity (e=0.44), 185-day orbit around a black hole. This orbit is difficult…

We report the results of a long-term spectroscopic monitoring of the FS\,CMa type object MWC\,728. We found that it is a binary system with a B5 Ve (T$_{\rm eff}$ = 14000$\pm$1000 K) primary and a G8 III type (T$_{\rm eff} \sim$ 5000 K)…

Previous studies have shown that many post-AGB stars with dusty disks are associated with single-lined binary stars. To verify the binarity hypothesis on a larger sample, we started a high-resolution spectral monitoring of about 40 field…

We present medium-resolution optical spectroscopy with the SOAR telescope of the O star secondary of the high-mass gamma-ray binary 1FGL J1018.6-5856 to help determine whether the primary is a neutron star or black hole. We find that the…

We present an analysis of the apsidal motion and light curve parameters of 54 never-before-studied galactic Algol-type binaries. This is the first analysis of such a large sample of eccentric eclipsing binaries in our Galaxy, and has…