346 citations · 4.9k across the 122 of their papers we have counts for
9 papers · 1 filter
A near-IR spectroscopic search for very-low-mass cool companions to notable DA white dwarfs
P. D. Dobbie, M. R. Burleigh, A. J. Levan +5
We have undertaken a detailed near-IR spectroscopic analysis of eight notable white dwarfs, predominantly of southern declination. In each case the spectrum failed to reveal compel…
Identification of a DO White Dwarf and a PG1159 Star in the ESO SN Ia Progenitor Survey (SPY)
K. Werner, T. Rauch, R. Napiwotzki +3
We present high-resolution VLT spectra of a new DO white dwarf and a new PG1159 star, which we identified in the ESO SPY survey. The PG1159 star is a low-gravity, extremely hot (Te…
3D-Kinematics of White Dwarfs from the SPY-Project
E-M. Pauli, U. Heber, R. Napiwotzki +2
We present kinematics of a sample of 398 DA white dwarfs from the SPY project (ESO SN Ia Progenitor surveY) and discuss kinematic criteria for a distinction of thin disk, thick dis…
Subluminous O stars from the ESO Supernova Progenitor Survey - Observation versus Theory
A. Stroeer, U. Heber, T. Lisker +2
The ESO Supernova Progenitor Survey (SPY) has identified 58 (mostly helium-rich) subluminous O stars. We use the Balmer line strength to distinguish sdO from He-sdO (no Balmer line…
Hot subdwarfs from the ESO Supernova Ia Progenitor Survey - I. Atmospheric parameters and cool companions of sdB stars
T. Lisker, U. Heber, R. Napiwotzki +4
We present the analysis of a high-resolution, high-quality sample of optical spectra for 76 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey (SPY). Effective temp…
A close binary nucleus in the most oxygen-poor planetary nebula PN G 135.9+55.9
G. H. Tovmassian, R. Napiwotzki, M. G. Richer +3
We report FUSE and new deep optical spectroscopic observations of PN G 135.9+55.9, the most oxygen-poor planetary nebula located in the Galactic halo. These observations allow us t…
Identification of a DO white dwarf and a PG1159 star in the ESO SN Ia progenitor survey (SPY)
K. Werner, T. Rauch, R. Napiwotzki +3
We present high-resolution VLT spectra of a new helium-rich DO white dwarf and a new PG1159 star, which we identified in the ESO SPY survey. We performed NLTE model atmosphere anal…
Double degenerates and progenitors of supernovae type Ia
R. Napiwotzki, L. Yungelson, G. Nelemans +12
We report on systematic radial velocity surveys for white dwarf - white dwarf binaries (double degenerates - DDs) including SPY (ESO Supernovae Ia progenitor survey) recently carri…
Close binary EHB stars from SPY
R. Napiwotzki, C. A. Karl, T. Lisker +5
We present the results of a radial velocity (RV) survey of 46 subdwarf B (sdB) and 23 helium-rich subdwarf O (He-sdO) stars. We detected 18 (39%) new sdB binary systems, but only o…