相关论文: The Hot Components of AM CVn Helium Cataclysmics

We have obtained observations of the ultraviolet spectrum of AM CVn, an ultra-short-period helium cataclysmic variable, using the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). We obtained data in…

We have applied grids of NLTE high gravity model atmospheres and optically thick accretion disk models for the first time to archival IUE and FUSE spectra of the S-type symbiotic variable EG And taken at superior spectroscopic conjunction…

We present an analysis of the FUSE spectra of eight high-declination dwarf novae obtained from a Cycle 7 FUSE survey. These DN systems have not been previously studied in the UV and little is known about their white dwarfs (WDs) or…

We have conducted a spectroscopic analysis of the far ultraviolet archival spectra of four symbiotic variables, EG And, AE Ara, CQ Dra and RW Hya. RW Hya and EG And have never had a recorded outburst while CQ Dra and AE Ara have outburst…

We present the results of a multi-component synthetic spectral analysis of the archival far ultraviolet spectra of several key nova-like variables including members of the SW Sex, RW Tri, UX UMa and VY Scl subclasses: KR Aur, RW Tri, V825…

We investigate the evolutionary properties of AM~CVn stars with massive white dwarf donors and accretors. As a representative of them we consider a binary initially composed by a 0.30 M$_\odot$, He WD and a 1.02 M$_\odot$, CO WD. We…

We report photometry of the helium-rich cataclysmic variable ES Ceti during 2001-2004. The star is roughly stable at V ~ 17.0 and has a light curve dominated by a single period of 620 s, which remains measurably constant over the 3 year…

AM Canum Venaticorum (AM CVn) stars are ultra-compact binary systems composed of a white dwarf (WD) primary accreting from a H-deficient donor. They are important as potential progenitors of Type Ia supernovae and laboratories for…

We present time-resolved spectroscopy of the AM CVn-type binaries GP Com and V396 Hya obtained with VLT/X-Shooter and VLT/UVES. We fully resolve the narrow central components of the dominant helium lines and determine radial velocity…

We calculate the heating and cooling of the accreting white dwarf (WD) in the ultracompact AM Canum Venaticorum (AM CVn) binaries and show that the WD can contribute significantly to their optical and ultraviolet emission. We estimate the…

We present a synthetic spectral analysis of nearly the entire FUV IUE archive of spectra of DNe in or near quiescence. We have examined all of the systems for which S/N permitted an analysis. The study includes 53 systems of all DN subtypes…

Current evolutionary models imply that most Cataclysmic Variables (CVs) have P_orb<2 hours and are Dwarf Nova (DN) systems that are quiescent most of the time. Observations of nearby quiescent DN find that the UV spectrum is dominated by…

We have carried out a spectroscopic analysis of the far ultraviolet spectra of six symbiotic variables. Two systems, LT Del, which has had one recorded outburst, and BD-21 3873 (= IV Vir) which has had no recorded outburst, are yellow…

We have obtained HST/STIS data for a total of eleven polars as part of a program aimed to compile a homogeneous database of high-quality far-ultraviolet (FUV) spectra for a large number of cataclysmic variables (CVs). Of the eleven polars,…

(Abridged) The Cataclysmic Variable (CV) population harbors a diverse range of donor stars and accreting white dwarfs (WDs). A range of WD masses is expected, from low mass Helium core WDs, to massive WDs which have previously accreted at…

AM CVn systems are ultra-compact, helium-rich, accreting binaries with degenerate or semi-degenerate donors. We report the discovery of five new eclipsing AM CVn systems with orbital periods of 61.5, 55.5, 53.3, 37.4, and 35.4 minutes.…

We present the results of XMM-Newton observations of four AM CVn systems -- AM CVn, CR Boo, HP Lib and GP Com. Their light curves show very different characteristics. The X-ray light curves show no coherent pulsations, suggesting the…

We present an extensive analysis of new light and radial-velocity (RV) curves, as well as high-quality broadening-function (BF) profiles of twelve binary systems for which a contact configuration with large temperature differencies between…

We report the results of a synthetic spectral analysis of Hubble STIS spectra of the AM CVn-type cataclysmic variable CP Eri obtained when the system was in quiescence. The FUV spectrum is best fitted by a helium-dominated, hybrid…

We present a 904-1183 A spectrum of the dwarf nova VW Hydri taken with the Far Ultraviolet Spectroscopic Explorer during quiescence, eleven days after a normal outburst, when the underlying white dwarf accreter is clearly exposed in the far…