• Publications
  • Influence
Present-day cosmic abundances - A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
Aims. A carefully selected sample of early B-type stars in OB associations and the field within the solar neighbourhood is studi ed comprehensively. Present-day abundances for the astrophysically
A Cosmic Abundance Standard: Chemical Homogeneity of the Solar Neighborhood and the ISM Dust-Phase Composition*
A representative sample of unevolved early B-type stars in nearby OB associations and the field is analyzed to unprecedented precision using NLTE techniques. The resulting chemical composition is
Temperature, gravity, and bolometric correction scales for non-supergiant OB stars
Context. Precise and accurate determinations of the atmospheric parameters effective temperature and surface gravity are mandatory to derive reliable chemical abundances in OB stars. Furthermore,
LMC origin of the hyper-velocity star HE 0437-5439. Beyond the supermassive black hole paradigm
Context. Hyper-velocity stars move so fast that only a supermassive black hole (SMBH) seems to be capable to accelerate them. Hence the Galactic centre (GC) is their only suggested place of ori gin.
Mixing of CNO-cycled matter in massive stars
Aims. We test predictions of evolution models on mixing of CNO-cycled products in massive stars from a fundamental perspective. Relative changes within the theoretical C:N:O abundance ratios and the
HD 271791: an extreme supernova runaway B star escaping from the galaxy
Hypervelocity stars (HVSs) were first predicted by theory to be the result of the tidal disruption of a binary system by a supermassive black hole (SMBH) that accelerates one component to beyond the
Fundamental properties of nearby single early B-type stars
Fundamental parameters of a sample of 26 apparently slowly-rotating single early B-type stars in the solar neighbourhood are presented and compared to high-precision data from detached eclipsing
C II Abundances in Early-Type Stars: Solution to a Notorious Non-LTE Problem
We address a long-standing discrepancy between non-LTE analyses of the prominent C II 4267 and 6578/82 A multiplets in early-type stars. A comprehensive non-LTE model atom of C II is constructed
HVS 7 - a chemically peculiar hyper-velocity star ⋆
Context. Hyper-velocity stars are suggested to originate from the dynamical interaction of binary stars with the supermassive black hole in the Galactic centre (GC), which accelerates one component
Dynamical mass of the O-type supergiant in ζ Orionis A
Aims. A close companion ofζ Orionis A was found in 2000 with the Navy Precision Optical Interferometer (NPOI), and shown to be a physical companion. Because the primary is a supergiant of type O, for