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The age of white dwarf companions
(2009)
We carried out a spectroscopic investigation of single lined white dwarfs (WDs) in double degenerate (DD) systems and discuss their binary evolution. Simulated spectra of the Hα region are used to derive upper limits on ...
Subdwarf B and O stars : which evolutionary pathways?
(2009)
Hot subdwarf stars (spectral types subdwarf B and O) are long lived stars producing a large amount of UV radiation. This makes them excellent candidates to explain the UV radiation observed in old populations. However, the ...
The B-type giant HD 271791 in the Galactic halo : Linking run-away stars to hyper-velocity stars
(2008-05-01)
Context. Young, massive stars have been found in the distant Galactic halo. Dynamical ejection from the Galactic disc has been suggested as the origin of these "run-away stars". The so-called hyper-velocity stars have been ...
Radial Velocity Variable sdO/Bs from SPY - Preliminary Orbits of Three New Short Period Binaries
(Astronomical Society of the Pacific, 2008)
We present new results from follow-up time-resolved spectroscopy of radial velocity variable hot subdwarfs from the SPY project. Medium resolu- tion spectra were taken at the ESO NTT. Preliminary orbital solutions are ...
The Origin of Helium-Rich Subdwarf O Stars
(Astronomical Society of the Pacific, 2008)
The origin of helium-rich subdwarf O stars (He-sdO) is still unclear. Significant progress has been made recently in placing them in the Hertzsprung–Russell diagram. However, the question of their progenitors is still ...
Recycling Matter in the Universe. X-ray observations of SBS 1150+599A (PN G135.9+55.9)
(American Institute of Physics (AIP), 2008)
We present X‐ray observations of the close binary nucleus of the planetary nebula SBS 1150+599A obtained with the XMM‐Newton satellite. Only one component of the binary can be observed in optical‐UV. New X‐ray observations ...
Binary sdB Stars with Massive Compact Companions
(Astronomical Society of the Pacific, 2008)
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close ...
Model Spectra of Hot Subdwarfs for the Gaia Mission
(Astronomical Society of the Pacific, 2008)
The Gaia mission will provide an unprecedented 3D view of our galaxy, it will obtain astrometric, photometric and spectrographic data for roughly one billion stars. We are particularly interested in the treasure chest of ...