相关论文: Multiwavelength Observations of the Hot DB Star PG…

We present the detection of non-radial oscillations in a hot, helium-atmosphere white dwarf using 78.7 d of nearly uninterrupted photometry from the Kepler space telescope. With an effective temperature >30,000 K, PG 0112+104 becomes the…

We present a series of systematic abundance measurements for 89 hot DA white dwarfs drawn from the FUSE observation archive. These stars span the temperature range ~ 20000-70000K, and form the largest sample to-date, exceeding our earlier…

Spectral analysis needs the observation of lines of successive ionization stages in order to evaluate the ionization equilibrium (of a particular species) which is a sensitive indicator for the effective temperature. Since stars with…

EC 11481-2303 is a peculiar, hot, high-gravity pre-white dwarf. Previous optical spectroscopy revealed that it is a sdOB star with an effective temperature (Teff) of 41790 K, a surface gravity log(g)= 5.84, and He/H = 0.014 by number. We…

We report early FUSE observations of the very hot DA white dwarfs PG1342+444 and REJ0558-371. Detection of photospheric absorption lines allows us to estimate the abundances of C, O, Si, P, S and Fe, the first measurements reported for DA…

We present a comprehensive study of Far Ultraviolet Spectroscopic Explorer (FUSE) spectra (912-1190 A) of two members of the PG1159 spectral class, which consists of hydrogen-deficient (pre-) white dwarfs with effective temperatures in the…

We present a first systematic investigation of the iron abundance in very hot (Teff>50,000K) hydrogen-deficient post-AGB stars. Our sample comprises 16 PG1159 stars and four DO white dwarfs. We use recent FUSE observations as well as HST…

We have observed the hot post-AGB star ZNG 1 in the globular cluster M5 with the Far Ultraviolet Spectroscopic Explorer (FUSE). From the resulting spectrum, we derive an effective temperature T_eff ~ 45,000 K, a rotational velocity v_rot ~…

High-resolution spectra of the hot white dwarf G191-B2B, covering the wavelength region 905-1187A, were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). This data was used in conjunction with existing high-resolution Hubble…

We present a detailed spectroscopic analysis of the hot DA white dwarf G191-B2B, using the best signal to noise, high resolution near and far UV spectrum obtained to date. This is constructed from co-added \textit{HST} STIS E140H, E230H,…

We present a detailed analysis of all the known Hot DQ white dwarfs in the Fourth Data Release of the Sloan Digital Sky Survey (SDSS) recently found to have carbon dominated atmospheres. Our spectroscopic and photometric analysis reveals…

We present a series of systematic abundance measurements for a group of hot DA white dwarfs in the temperature range 20,000-75,000K, based on far-UV spectroscopy with STIS on HST, IUE and FUSE. Using our latest heavy element blanketed…

PG1159 stars are hot hydrogen-deficient post-AGB stars with effective temperatures within a range from 75000 K up to 200000 K. These stars are probably the result of a late helium-shell flash that had occurred during their first descent…

LS V +4621 is the DAO-type central star of the planetary nebula Sh 2-216. We perform a comprehensive spectral analysis of high-resolution, high-S/N ultraviolet observations obtained with FUSE and STIS aboard the HST as well as the optical…

We have analyzed FUSE observations of six hot white dwarf stars: four DA white dwarfs with T_eff >= 45000K, the DAO Feige55 (T_eff = 55000K), and the DA CD -38 10980 (T_eff = 24000K). Photospheric lines from SiIV, PV, and SVI can be…

We report a high-resolution (R=3000-4000) spectroscopic observation of the DA white dwarf G191-B2B in the extreme ultraviolet band 220-245 A. A low- density ionised He component is clearly present along the line-of-sight, which if…

Atmospheric parameters for hot DB (helium atmosphere) white dwarfs near effective temperatures of 25000K are extremely difficult to determine from optical spectroscopy. This is particularly unfortunate, because this is the range of variable…

We report observations of the hot post-asymptotic giant branch star ZNG 1 in the globular cluster M5 (NGC 5904) with the Far Ultraviolet Spectroscopic Explorer (FUSE). From the resulting spectrum, we derive an effective temperature T_eff =…

We show that the blue 18.3-minute variable object discovered in the Galactic disk by the OGLE-III survey and named OGLE-GD-WD-0001 is a pulsating pre-white dwarf of PG 1159 spectral type. With an effective temperature of about 160,000 K it…

PG1159 stars are hot, hydrogen-deficient (pre-) white dwarfs with atmospheres mainly composed of helium, carbon, and oxygen. The unusual surface chemistry is the result of a late helium-shell flash. Observed element abundances enable us to…