Related papers: Hot Subdwarfs in Resolved Binaries
The theoretical discription of a hot star interior is obtained. It explains the distribution of stars over their masses, mass-radius-temperature and mass-luminosity dependencies. The theory of the apsidal rotation of binary stars and the…
Young, intermediate-mass stars are experiencing renewed interest as targets for direct-imaging planet searches. However, these types of stars are part of multiple systems more often than not. Close stellar companions affect the formation…
Massive stars feature highly energetic stellar winds that interact whenever two such stars are bound in a binary system. The signatures of these interactions are nowadays found over a wide range of wavelengths, including the radio domain,…
The statistical properties of planets in binaries were investigated. Any difference to planets orbiting single stars can shed light on the formation and evolution of planetary systems. As planets were found around components of binaries…
Hot subdwarf B stars (sdBs) in close binary systems are assumed to be formed via common envelope ejection. According to theoretical models, the amount of energy and angular momentum deposited in the common envelope scales with the mass of…
Photometric surveys at optical, ultraviolet, and infrared wavelengths provide ever growing datasets as major surveys proceed. Colour-colour diagrams are useful tools to identify classes of stars and to provide large samples. Combining all…
With the advent of large-collecting-area instruments, the number of objects that can be reached by optical long-baseline interferometry is steadily increasing. We present here a few results on massive binary stars, showing the interest of…
Wide binaries are tracers of the gravity field of the Galaxy, but their study requires some caution. A large list of common proper motion stars selected from the AGK3 were monitored with the CORAVEL spectrovelocimeter, in order to prepare a…
The origin of subluminous B stars is still an unsolved problem in stellar evolution. Single star as well as close binary evolution scenarios have been invoked but until now have met with little success. We have carried out a small survey of…
Most Sun-like and higher-mass stars reside in systems that include one or more gravitationally bound stellar companions. These systems offer an important probe of planet formation in the most common stellar systems, while also providing key…
Hot subdwarfs are compact blue evolved objects, burning helium in their cores surrounded by a tiny hydrogen envelope. Most models agree on a common envelope binary evolution scenario in the Red Giant phase. However, the binarity rate for…
Binary stars can inflate the observed velocity dispersion of stars in dark matter dominated systems such as ultra-faint dwarf galaxies (UFDs). However, the population of binaries in UFDs is poorly constrained by observations, with preferred…
We report on our large scale search of 2MASS and SuperCOSMOS in the southern hemisphere for very widely separated white dwarf / L-dwarf binary systems and present our findings, including 8 widely separated candidate systems, and proper…
We describe a near-IR photometric search for cool red dwarf companions to hot EUV-detected white dwarfs (WDs). While some composite systems have been found optically among WDs detected in recent EUV All-Sky Surveys, we develop an IR…
Binary-star exoplanetary systems are now known to be common, for both wide and close binaries. However, their orbital evolution is generally unsolvable. Special cases of the N-body problem which are in fact completely solvable include…
We started a new project which aims to find compact hot subdwarf binaries at low Galactic latitudes. Targets are selected from several photometric surveys and a spectroscopic follow-up campaign to find radial velocity variations on…
We perform stellar evolution calculations of the remnant of the merger of two He white dwarfs (WDs). Our initial conditions are taken from hydrodynamic simulations of double WD mergers and the viscous disc phase that follows. We evolve…
In this paper we review some recent detections of wide binary brown dwarf systems and discuss them in the context of the multiplicity properties of very low-mass stars and brown dwarfs.
Situation with highly magnetized neutron stars in binary systems is not yet certain. On the one hand, all best studied magnetars seem to be isolated objects. On the other, there are many claims based on model-dependent analysis of spin…
There is growing evidence that some Be stars were spun up through mass transfer in a close binary system, leaving the former mass donor star as a hot, stripped-down object. There are five known cases of Be stars with hot subdwarf (sdO)…