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Spectroscopic Analysis of Subluminous B Stars in Binaries with Compact Companions
(Astronomical Society of the Pacific, 2007)
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 ...
Testing Magnetic Braking: The X-ray Activity of M Dwarfs in Pre-Cataclysmic Variable Systems
(Astronomical Society of the Pacific, 2007)
Angular momentum loss by magnetic braking is believed to be an important mechanism in the evolution of tidally-locked white dwarf (WD) bina- ries. We measure the X-ray emission of a sample of M dwarfs in pre-cataclysmic ...
An object that defies stereotypes : X-ray observations of SBS 1150+599A - the binary nucleus of PN G135.9+55.9
(2007)
We present X-ray observations of the close binary nucleus of the planetary nebula (PN) PN G135.9+55.9 obtained with the XMM satellite. The nebula is the most oxygen-poor PN known to date and is located in the Galactic halo. ...
Binary White Dwarfs in the Supernova Ia Progenitor Survey
(Astronomical Society of the Pacific, 2007)
We report results of a systematic radial velocity survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae: SPY (ESO Supernovae Ia Progenitor surveY). More than 1000 white dwarfs (WDs) and ...
The Fraction of DA White Dwarfs with Kilo-Gauss Magnetic Fields
(Astronomical Society of the Pacific, 2007)
Current estimates for white dwarfs with fields in excess of 1MG are about 10%; according to our first high-precision circular-polarimetric study of 12 bright white dwarfs with the VLT (Aznar Cuadrado et al. 2004) this ...
White Dwarfs in the European Galactic Plane Surveys (EGAPS)
(Astronomical Society of the Pacific, 2007)
The space density of white dwarfs is highly uncertain even nearby. This results from the fact that the known sample of white dwarfs is largely in- complete in part because most white dwarfs have been discovered as by-products ...
The Origins of the Ultramassive White Dwarf GD50
(Astronomical Society of the Pacific, 2007)
On the basis of astrometric and spectroscopic data we argue that the ultramassive white dwarf GD 50 is associated with the star formation event that created the Pleiades and is potentially a former cluster member. Its ...
3D-Kinematics of White Dwarfs from the SPY-Project
(Astronomical Society of the Pacific, 2007)
We present a progress report on the kinematical analysis of the entire SPY (ESO SN Ia Progenitor surveY; see Napiwotzki et al. 2001) sample of about one thousand white dwarfs and hot subdwarfs. In a previous study (Pauli ...
Follow-up Observations of SPY White Dwarf + M-Dwarf Binaries
(Astronomical Society of the Pacific, 2007)
We present the results of follow-up observations of white-dwarf + M-dwarf binaries identified using spectra obtained as part of the SPY survey. Spectra of the Hα region were obtained with the SPIRAL spectrograph on the AAT ...