The brightness and colour of a star are determined by factors such as mass, age and metallicity but can also be affected by the presence of an unresolved companion. Any discussion of stellar evolution on the H-R diagram must involve a consideration stellar multiplicity. For example, a young binary system at low metallicity may be bright enough such that it resembles an evolved single star at...
Single-degenerate massive binaries containing a black hole (OB+BH) represent an important evolutionary phase on the pathway of becoming BH mergers. In the past two years, several OB+BHs were reported to exist on the basis of spectroscopic investigations. However, most reported OB+BH systems were later challenged by follow-up studies, demonstrating the extreme difficulty to identify BHs using...
In preparation for the release of the astrometric orbits of Gaia, Shahaf, Mazeh, Faigler, and Holl (2019) proposed a triage technique to identify hierarchical triples and astrometric binaries that have compact companions. The classification is done based on the astrometric semi-major axis, the parallax, and the primary mass, and relies upon the use of an appropriate mass-luminosity relation....
The recently published Gaia DR3 catalog of 181,327 spectroscopic binaries (SB) includes the Keplerian elements of each orbit, but not the measured radial velocities (RVs) and their epochs themselves. In this work, we used two external sources to validate the orbits - LAMOST DR6 and GALAH DR3 stars with measured RVs that have Gaia-SB orbits. We compared the expected RVs, based on the Gaia...
