Related papers: Binary Masses as a Test for Pre-Main-Sequence Mode…

Context: One of the greatest uncertainties in modelling the mass-exchange phases during the evolution of a binary system is the amount of mass and angular momentum that has been lost from the system. To constrain this problem, a favourable,…

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…

We report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5 - 15 arcmin (0.65 - 2 pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find…

We present orbital elements and mass sums for eighteen visual binary stars of spectral types B to K (five of which are new orbits) with periods ranging from 20 to more than 500 yr. For two double-line spectroscopic binaries with no previous…

We aim at unveiling the observational imprint of physical mechanisms that govern planetary formation in young, multiple systems. In particular, we investigate the impact of tidal truncation on the inner circumstellar disks. We observed the…

The orbital parameters of binaries at intermediate periods ($10^2$--$10^3$ d) are difficult to measure with conventional methods and are very incomplete. We have undertaken a new survey, applying our pulsation timing method to {\it Kepler}…

The complexity of composite spectra of close binaries makes the study of the individual stellar spectra extremely difficult. For this reason there exists very little information on the chemical composition of high-mass stars in close…

This paper reviews methods which can be used to detect binaries involving low- and intermediate-mass stars, with special emphasis on evolved systems. Besides the traditional methods involving radial-velocity or photometric monitoring, the…

Evolutionary models of pre-main sequence stars remain largely uncalibrated, especially for masses below that of the Sun, making each new dynamical mass and radius measurement a valuable test of theoretical models. Stellar mass dependent…

We present a consistent age ordering for young clusters and groups determined using the contraction of stars through their pre-main-sequence phase. We compare these with ages derived from the evolution of the upper main-sequence stars, and…

This paper presents and discusses a critical compilation of accurate, fundamental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and alpha Centauri) that…

We explore the initial conditions that lead to detached binary evolution of massive pre-MS binaries and ask how large a fraction of the observed binary systems may have been initially formed as low-mass protobinaries and later undergone a…

The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but…

The measurement or constraint of the masses of neutron stars and their binary companions tests theories of neutron star structure and of pulsar formation and evolution. We have measured the rate of the general relativistic advance of the…

We present the results of time-resolved spectroscopy of 13 O-type stars in the Cas OB6 stellar association. We conducted a survey for radial velocity variability in search of binary systems, which are expected to be plentiful in young OB…

We present the results of an analysis aimed at testing the accuracy and precision of the PARSEC v1.2S library of stellar evolution models, in a Bayesian framework, to infer stellar parameters. We mainly employ the online DEBCat catalogue by…

Observations of young star-forming regions suggest that star clusters are born completely mass segregated. These initial conditions are, however, gradually lost as the star cluster evolves dynamically. For star clusters with single stars…

Observations indicate that in young stellar clusters the binary fraction for massive stars is higher than for solar mass stars. For the Orion Nebula Cluster (ONC) there is a binary frequency of ~ 50% for solar-mass stars compared to 70-100%…

We present an astrometric/spectroscopic orbital solution for the pre-main-sequence binary NTT 045251+3016. Our measurements for the primary and secondary masses are 1.45 +/- 0.19 M_sun and 0.81 +/- 0.09 M_sun, respectively, and 145 +/- 8 pc…

We develop a statistical test on the expected difference in age estimates of two coeval stars in detached double-lined eclipsing binary systems that are only caused by observational uncertainties. We focus on stars in the mass range [0.8;…