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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. ...
The Subdwarf B + White Dwarf Binary KPD 1930+2752, a Supernova Type Ia Progenitor Candidate
(Astronomical Society of the Pacific, 2007)
The nature of the progenitors of type Ia supernovae is still under controversial debate. KPD 1930+2752 is one of the best SN Ia progenitor can- didates known today. The object is a double degenerate system consisting of a ...
Six New ZZ Ceti Stars from the SPY and the HQS Surveys
(Astronomical Society of the Pacific, 2007)
We report on the discovery of six new ZZCeti stars. They were selected as candidates based on preparatory photometric observations of ob- jects from the Hamburg Quasar Survey (HQS), and based on the spectra of the Supernova ...
Discovery of the First Very Wide WD LD Binary System
(Astronomical Society of the Pacific, 2007)
We report on our large scale search of 2MASS and SuperCOS- MOS in the southern hemisphere for very widely separated white dwarf / L-dwarf binary systems and present our findings, including eight widely separated can- didate ...
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 ...