7 papers · 1 filter
A systematic survey for hypervelocity runaways from thermonuclear supernovae
Kareem El-Badry, Klaus Werner, Ken J. Shen +16
The explosion of a white dwarf (WD) in a close binary can launch a surviving runaway star at velocities of . Such runaways provide a direct probe of…
Spectroscopic survey of faint planetary-nebula nuclei. VII. Thirty new hydrogen-deficient central stars
Klaus Werner, Howard E. Bond, Gregory R. Zeimann
Our ongoing spectroscopic survey of faint planetary-nebula nuclei (PNNi) has revealed 30 new hydrogen-deficient central stars. The majority of them (21) belong to the PG1159 spectr…
Spectral evolution of hot hybrid white dwarfs: II. Photometry
Semih Filiz, Nicole Reindl, David Jones +4
We present a photometric analysis of 19 DA and 13 DAO white dwarfs (WDs) with effective temperatures exceeding 60 kK, building on the spectral analysis reported in the first paper…
How an overweight and rapidly rotating PG 1159 star in the Galactic halo challenges evolutionary models
Nina Mackensen, Nicole Reindl, Klaus Werner +2
PG 1159 stars are thought to be progenitors of the majority of H-deficient white dwarfs. Their unusual He-, C-, and O-dominated surface composition is typically believed to result…
Three new hot hydrogen-deficient pre-white dwarfs
Klaus Werner, Nicole Reindl, Max Pritzkuleit +1
We have detected three new hydrogen-deficient (H < 0.001 mass fraction) pre-white dwarfs (WDs) with helium-dominated atmospheres. The first object is a relatively cool PG1159 star…
An analysis of spectroscopic, seismological, astrometric, and photometric masses of pulsating white dwarf stars
Leila M. Calcaferro, Alejandro H. Córsico, Murat Uzundag +3
A central challenge in the field of stellar astrophysics lies in accurately determining the mass of isolated stars. However, for pulsating white dwarf (WD) stars, the task becomes…