Related papers: A search for binarity using FUSE observations of D…
We present heavy element abundance measurements for 16 DAO white dwarfs, determined from Far-Ultraviolet Spectroscopic Explorer {FUSE} spectra. Evidence of absorption by heavy elements was found in the spectra of all the objects.…
We present a small collection of FUSE spectra representative of the main spectral classes found in white dwarf stars. In addition, we also discuss another family of hot evolved stars, that of the hot subdwarfs. Both families belong to the…
The number of spatially unresolved white dwarf plus main-sequence star binaries has increased rapidly in the last decade, jumping from only ~30 in 2003 to over 3000. However, in the majority of known systems the companion to the white dwarf…
White dwarfs with a F, G or K type companion represent the last common ancestor for a plethora of exotic systems throughout the galaxy, though to this point very few of them have been fully characterised in terms of orbital period and…
We present the results of a high-resolution imaging survey of 22 brown dwarfs and very low mass stars in the nearby (~145 pc) young (~1-2 Myr) low-density star-forming region Taurus-Auriga. We obtained images with the Advanced Camera for…
The ROSAT WFC survey has provided us with evidence for the existence of a previously unidentified sample of hot white dwarfs (WD) in non-interacting binary systems, through the detection of EUV and soft X-ray emission. These stars are…
We present FUSE observations of the hot white dwarfs in the post-common envelope binaries Feige 24, EUVE J0720-317, BPM 6502, and EUVE J2013+400. The spectra show numerous photospheric absorption lines which trace the white dwarf orbital…
The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies…
The far-ultraviolet spectrum of the DAO White Dwarf LS V+4621, the exciting star of the possible planetary nebula Sh 2-216,is strongly contaminated by absorption features from the interstellar medium (ISM). For an ongoing spectral analysis,…
FUSE observations have been instrumental in advancing our understanding of the physical properties and behavior of active binary systems, including cataclysmic variables (CVs) and X-ray binaries (XRBs). FUSE data have allowed observers to…
We examine 14 hot white dwarfs for signs of infrared excess using the Spitzer Space Telescope. Twelve of the objects are massive white dwarfs which have been suggested to be the result of binary mergers. The remaining two objects are…
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…
Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…
We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All…
Primordial evaluations of the deuterium abundance should provide one of the best tests of Big Bang nucleosynthesis models. Space as well as ground based observations seem however to result in different values. This asks for more…
We report on the spectroscopic confirmation of 68 new bright ($G=13.5-17.2$ mag) and blue (pre-)white dwarfs (WDs). This finding has allowed us to almost double the number of the hottest ($T_{\mathrm{eff}} \geq 60$kK) known WDs brighter…
We present highlights and an overview of 20 FUSE and HST/STIS observations of the bright symbiotic binary EG And. The main motivation behind this work is to obtain spatially-resolved information on an evolved giant star in order to…
Archival data from the WISE satellite reveals infrared flux variations of tens of per cent around numerous dusty white dwarfs. Data spanning more than seven years reveal more than half of known systems are varying in the 3.4 micron band,…
We present our findings on the spectral analysis of seven magnetic white dwarfs that were presumed to be double degenerates. We obtained time-resolved spectroscopy at the Gemini Observatory to look for evidence of binarity or fast rotation.…
We present a deuterium abundance analysis of the line of sight toward the white dwarf WD2211-495 observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). Numerous interstellar lines are detected on the continuum of the stellar…