Related papers: The Multiplicity of the Hyades and its Implication…
The Hyades constitute a homogeneous sample of stars ideal for investigating the dependence of planet formation on the mass of the central star. Due to their youth, Hyades members are much more chromospherically active than stars…
We present low-resolution optical spectra of each component of 10 T Tauri (TT) binary systems with separations ranging from 0.9" to 3.5" and located in the Taurus star-forming region. We derive the spectral type and Halpha equivalent width…
Gaia observations have revealed over a million stellar binary candidates within ~1 kpc of the Sun, predominantly characterized by orbital separations >10^3 AU and eccentricities >0.7. The prevalence of such wide, eccentric binaries has…
It has now been known for over a decade that low-mass stars located in star-forming regions are very frequently members of binary and multiple systems, even more so than main sequence stars in the solar neighborhood. This high multiplicity…
Context. Establishing the multiplicity of O-type stars is the first step towards accurately determining their stellar parameters. Moreover, the distribution of the orbital parameters provides observational clues to the way that O-type stars…
Individual components of well-detached binary systems are assumed to be two single-like stars with a common origin, i.e. they share the same chemical composition and same age. Therefore, one expects to fit the observed parameters of both…
Multiple star systems are commonly assumed to form coevally; they thus provide the anchor for most calibrations of stellar evolutionary models. In this paper we study the binary population of the Taurus-Auriga association, using the…
Previous studies on the rotation of Sun-like stars revealed that the rotational rates of young stars converge towards a well-defined evolution that follows a power-law decay. It seems, however, that some binary stars do not obey this…
We have used data from the UKIRT Hemisphere Survey (UHS) to search for substellar members of the Hyades cluster. Our search recovered several known substellar Hyades members, and two known brown dwarfs that we suggest may be members based…
Identifying and removing binary stars from stellar samples is a crucial but complicated task. Regardless of how carefully a sample is selected, some binaries will remain and complicate interpretation of results, especially via flux…
The frequency of planets in binaries is an important issue in the field of extrasolar planet studies because of its relevance in the estimation of the global planet population of our galaxy and the clues it can give to our understanding of…
Abundances of 15 chemical elements have been derived for 28 F and 16 A stars members of the Hyades open cluster in order to set constraints on self-consistent evolutionary models including radiative and turbulent diffusion. A spectral…
Data on the multiplicity of F- and G-type dwarf stars within 67pc of the Sun are presented. This distance-limited sample based on the Hipparcos catalog contains 4847 primary stars (targets) with 0.5<V-I_C<0.8 and is >90% complete. There are…
We present updated results from our near-infrared long-baseline interferometry (LBI) survey to constrain the multiplicity properties of intermediate-mass A-type stars within 80 pc. Previous adaptive optics surveys of A-type stars are…
Various surveys of low-mass binaries in star forming regions have been performed in recent years. They reached opposite conclusions concerning possible binary excesses in some of these associations. I develop a consistent method to…
The complexity of composite spectra of close binary star system makes study of the spectra of their component stars extremely difficult. For this reason there exists very little information on the photospheric chemical composition of stars…
Masses of classical Cepheids of 3 to 11 M$\odot$ are predicted by theory but those measured, clump between 3.6 and 5 M$\odot$. As a result, their mass-luminosity relation is poorly constrained, impeding our understanding of basic stellar…
The Hyades cluster is known to harbour ten so-called classical white dwarf members. Numerous studies through the years have predicted that more than twice this amount of degenerate stars should be associated with the cluster. Using the…
On the basis of the PPMXL catalogue (R\"oser, Demleitner & Schilbach, 2010) we searched for white dwarfs that are also member candidates of the Hyades in a region up to 40 pc from the cluster centre. We use the proper motions from PPMXL in…
Binary stars are common in star clusters and galaxies, but the detailed effects of binary evolution are not taken into account in some colour-magnitude diagram (CMD) studies. This paper studies the CMDs of twelve globular clusters via…