Aims. We use Gaia Data Release 2 (DR2) to place 252 Herbig Ae/Be stars in the
Hertzsprung–Russell diagram and investigate their characteristics and properties. Methods …

Context. Binary evolution can result in fast-rotating stars through accretion of angular
momentum during mass-transfer phases. These fast-rotating stars are predicted to be …

Rapid rotation is a fundamental characteristic of classical Be stars and a crucial property
allowing for the formation of their circumstellar disks. Past evolution in a mass and angular …

Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the
characteristic line emission forms. A major but unconstrained fraction of Be stars owe their …

ABSTRACT X-ray binaries (XRBs) are thought to regulate cosmic thermal and ionization
histories during the Epoch of Reionization and Cosmic Dawn (z∼ 5–30). Theoretical …

Be X-ray binaries (Be-XRBs) are one of the largest subclasses of high-mass X-ray binaries,
comprised of a rapidly rotating Be star and neutron star companion in an eccentric orbit …

Be stars are main-sequence massive stars with emission features in their spectrum, which
originates in circumstellar gaseous discs. Even though the viscous decretion disc model can …

Context. The intermediate-mass pre-main sequence Herbig Ae/Be stars are key to
understanding the differences in formation mechanisms between low-and high-mass stars …

Classical Be stars are possible products of close binary evolution, in which the mass donor
becomes a hot, stripped O-or B-type subdwarf (sdO/sdB), and the mass gainer spins up and …

Context. Many physical processes taking place during the evolution of binary stellar systems
remain poorly understood. The ever-expanding observational sample of X-ray binaries …