相关论文: FUSE Observations of the Symbiotic Star AG Draconi…
Far Ultraviolet Spectroscopic Explorer FUSE observations of the bright binary system Capella (Alpha Aurigae; G1 III + G8 III) reveal a rich emission line spectrum containing neutral and ionic species, among them H I, O I, C III, O VI, S VI,…
Far ultraviolet spectra were obtained of the active cool star AB Doradus (HD 36705) during the calibration and checkout period of the FUSE satellite. Observations in this early phase of the mission were taken at a resolving power of…
AG Dra is one of a small group of low metallicity S-type symbiotic binaries with K-type giants that undergoes occasional short-term outbursts of unknown origin. Our aim is to study the behavior of the white dwarf during an outburst using…
One of the strongest absorption lines observed in far-ultraviolet FUSE spectra of many PG1159 stars remained unidentified up to now. We show that this line, located at 973.3A, stems from NeVII. We also present new optical high-resolution…
The modeling of UV and optical spectra emitted from the symbiotic system AG Draconis, adopting collision of the winds, predicts soft X-ray bremsstrahlung from nebulae downstream of the reverse shock with velocities > 150 km/s and…
We report the detection of diffuse O VI 1032, 1038 A emission in a 29-ksec observation centered on the Coma Cluster (l = 57.6, b = +88.0) and an 11-ksec observation toward Virgo (l = 284.2, b = +74.5) through the low-resolution (30"x30")…
We present the first observations of a Herbig Ae star with a circumstellar disk by the Far Ultraviolet Spectroscopic Explorer (FUSE), as well as a simultaneous observation of the star obtained with the Hubble Space Telescope Space Telescope…
Variations of the emission lines in the spectrum of the yellow symbiotic star AG Dra have been studied for over 14 years (1997 - 2011), using more than 500 spectra obtained on the 1.5-metre telescope at Tartu Observatory, Estonia. The time…
AG Dra is a symbiotic variable consisting of a metal poor, yellow giant mass donor under-filling its Roche lobe, and a hot accreting white dwarf, possibly surrounded by an optically thick, bright accretion disk which could be present from…
[Abridged] We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the young, compact planetary nebula (PN) SwSt 1 along the line of sight to its central star HD 167362. We detect circumstellar absorption lines from several…
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…
Thirteen transitions within the ground 3d^2 configuration of Fe VII are identified in ultraviolet and optical spectra of the symbiotic star RR Telescopii obtained with the STIS instrument of the Hubble Space Telescope. The line fluxes are…
The interstellar abundances of D I, N I, and O I in the local ISM are studied us ing high-resolution spectra of four hot white dwarfs. The spectra of GD 246, WD 2331$-$475, HZ 21, and Lan 23 were obtained with the {\it Far Ultraviolet…
We present spectroscopic observations of the short-period cataclysmic variable SW Ursa Majoris, obtained by the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite while the system was in quiescence. The data include the resonance lines…
Fully relativistic calculations of radiative rates and electron impact excitation cross sections for Fe X are used to derive theoretical emission-line ratios involving transitions in the 174-366 A wavelength range. A comparison of these…
The appearance of the young supernova remnant SN1006 is dominated by emission from non-radiative shocks in the NE and NW regions. At X-ray energies the northeast shock exhibits predominantly nonthermal synchrotron emission, while the…
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…
Six high-resolution (\lambda/\Delta\lambda ~ 3000) far-UV (\lambda\lambda = 910-1210 \AA) spectra of the magnetic cataclysmic variable AM Herculis were acquired in 1996 November during the flight of the ORFEUS-SPAS II mission. AM Her was in…
We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of the ultramassive (M = 1.31 solar mass), magnetic (B_s = 2.3 MG) white dwarf PG 1658+441. The far ultraviolet (FUV) spectrum exhibits very broad Lyman…
Symbiotic stars are strongly interacting binaries, consisting of a white dwarf and a cool giant, mainly of spectral type M. AG Draconis belongs to a less numerous group of the yellow symbiotic systems, as the cool component in this binary…