相关论文: U Geminorum: a test case for orbital parameters de…

We present a phase-resolved spectroscopic study of the secondary star in the cataclysmic variable U Gem. We use our data to measure the radial velocity semi-amplitude, systemic velocity and rotational velocity of the secondary star.…

U Gem is unique in having a direct measurement of K1 = 107 +- 2 km/s, Long et al. 1999). We present high-resolution optical spectra of the dwarf nova U Gem in quiescence taken to test the accuracy to which the HST value can be recovered…

We present new optical spectroscopic observations of U Geminorum obtained during a quiescent stage. We performed a radial velocity analysis of three Balmer emission lines yielding inconsistent results. Assuming that the radial velocity semi…

We have obtained FUV (904 -- 1187 \AA) spectra of U Gem in outburst with FUSE. Three of the observations were acquired during the plateau phase of the outburst, while the fourth was obtained during late outburst decline. The plateau spectra…

We describe new optical photometric and spectroscopic observations of the semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg I absorption at secondary maximum indicates the presence of cool material in the outer…

Observations of U Gem with FUSE confirm that the WD is heated by the outburst and cools during quiescence. At the end of an outburst, the best uniform temperature WD model fits to the data indicate a temperature of 41,000 - 47,000 K, while…

System parameters are re-determined: $M_1=0.86\pm0.18M\odot$, $M_2=0.103\pm0.022M\odot$, $A=1.508\pm 0.100\times 10^{10}$cm, and $i=69\pm3^{\circ}$. The secondary component is a semi-degenerate helium star loosing mass at a rate $\dot…

Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to search for hot binary companions to cool AGB…

We derive precise system parameters for the pre-cataclysmic binary, NN Ser. From light curve fitting we find an orbital inclination of i = 89.6 +/- 0.2 deg. From the HeII absorption line we find K_{WD}= 62.3 +/- 1.9 km/s. The…

Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to look for hot binary companions to cool AGB stars…

We present the results of the first high-sensitivity NUV (1800 to 3200 \AA) survey of FU Ori objects, using the \textit{Hubble Space Telescope} (HST) STIS spectrograph. We compare new low resolution spectra for 6 sources with predictions…

We investigated the nature of the hitherto unresolved elliptical infrared emission in the centre of the ~20000 AU disc silhouette in M 17. We combined high-resolution JHKsL'M' band imaging carried out with NAOS/CONICA at the VLT with [Fe…

Spectroscopic observations of AH Herculis during a deep quiescent state are put forward. We found the object in a rare long minima, allowing us to derive accurately the semi-amplitudes: $K_1 =121 \pm \, 4$ \kms\ and $K_2 =152 \pm 2$ \kms\…

We have used HST/COS to obtain a series of 4 FUV (915-2148A) spectroscopic observations of the prototypical dwarf nova U Geminorum during its cooling following a two-week outburst. Our FUV spectral analysis of the data indicates that the…

We present phase-resolved spectroscopy of the eclipsing AM Herculis star UZ For obtained when the system was in its low state of accretion. Faint residual Halpha-emission and NaI absorption were used to trace the secondary star and infer…

We present a near-infrared study of the Seyfert 2 galaxy NGC\,6300, based on subarcsecond images and long slit spectroscopy obtained with Flamingos-2 at Gemini South. We have found that the peak of the nuclear continuum emission in the…

We present precise stellar radial velocity measurements for the K giant star Beta Gem spanning over 25 years. These data show that the long period low amplitude radial velocity variations found by Hatzes & Cochran (1993) are long-lived and…

We obtained Hubble GHRS medium resolution (G160M grating) phase-resolved spectroscopic observations of the prototype dwarf nova U Geminorum during dwarf nova quiescence, 13 days and 61 days following the end of a narrow outburst. The…

We have obtained intermediate resolution optical spectra of the black-hole candidate Nova Sco 1994 in June 1996, when the source was in an X-ray/optical active state (R~15.05). We measure the radial velocity curve of the secondary star and…

We modelled optical light curves of Sco~X-1 obtained by the Kepler space telescope during K2 mission. Modelling was performed for the case of the strong heating of the optical star and accretion disc by X-rays. In the considered model the…