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A continuous photometric study of 12 novae was carried out for more than 365 nights during the past 4 years at the Wise Observatory in a motivation to extend our knowledge on these systems. Main results: we found observational evidence for…

Astrophysics · Physics 2009-10-31 A. Retter

Since the large amplitude 2007 outburst which heated its accreting, pulsating white dwarf, the dwarf nova system GW Librae has been cooling to its quiescent temperature. Our Hubble Space Telescope ultraviolet spectra combined with…

Double-lined eclipsing binaries allow accurate and direct determination of fundamental parameters such as mass and radius for each component, and they provide important constraints on the stellar structure and evolution models. In this…

Solar and Stellar Astrophysics · Physics 2018-03-14 Jang-Ho Park , Kyeongsoo Hong , Jae-Rim Koo , Jae Woo Lee , Chun-Hwey Kim

We examine published observations of dwarf nova oscillations (DNOs) on the rise and decline of outbursts and show that their rates of change are in reasonable agreement with those predicted from the magnetic accretion model. We find…

Astrophysics · Physics 2009-11-13 Brian Warner , Magaretha L. Pretorius

Novae are cataclysmic variable binary systems in which a white dwarf primary is accreting material from a low mass companion. The importance of this accretion takes on added significance if the WD can increase its mass to reach the…

Solar and Stellar Astrophysics · Physics 2013-03-18 G. Newsham , S. Starrfield , F. Timmes

Low-resolution spectra from 3000-9000 AA of young low-mass stars and brown dwarfs were obtained with LRIS on Keck I. The excess UV and optical emission arising in the Balmer and Paschen continua yields mass accretion rates ranging from…

Astrophysics · Physics 2009-06-23 Gregory J. Herczeg , Lynne A. Hillenbrand

The multicolour photometric observations of the neglected eclipsing binary FT Ursae Majoris (FT UMa) were obtained in 2010. The 2003 version of Wilson-Devinney code was used to analyze the light curves in $B$, $V$, and $R$ bands…

Solar and Stellar Astrophysics · Physics 2015-05-28 Jin-Zhao Yuan

We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii during the 2006 November outburst During the outburst, superhumps were unambiguously detected with a mean period of 0.078828(6) days, firstly classifying the…

The 10th recorded outburst of the recurrent eclipsing nova USco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after outburst. Two full passages of the companion in front of the nova ejecta were…

EX Dra is a long-period eclipsing dwarf nova with $\sim2-3$ mag amplitude outbursts. This star has been monitored photometrically from November, 2009 to March, 2016 and 29 new mid-eclipse times were obtained. By using new data together with…

Astrophysics of Galaxies · Physics 2017-06-28 Zhong-tao Han , Sheng-bang Qian , Irina Voloshina , Li-Ying Zhu

The UV spectra of nova-like variables are dominated by emission from the accretion disk, modified by scattering in a wind emanating from the disk. Here we model the spectra of RW Tri and UX UMa, the only two eclipsing nova-likes which have…

Solar and Stellar Astrophysics · Physics 2010-08-11 Ulrich M. Noebauer , Knox S. Long , Stuart A. Sim , Christian Knigge

We report a study of the spectra and structure of the accretion disk of the dwarf nova V2051 Ophiuchi while the star was in an unusual faint brightness state during 1996. The differences between the UV resonant lines and continuum disk…

Astrophysics · Physics 2007-05-23 R. K. Saito , R. Baptista

We investigate the time evolution of luminous accretion disks around black holes, conducting the two-dimensional radiation-hydrodynamic simulations. We adopt the alpha prescription for the viscosity. The radial-azimuthal component of…

Astrophysics · Physics 2009-11-11 K. Ohsuga

We examine the light curve of the July-August 2001 superoutburst of WZ Sagittae. During the decline from maximum light the locally defined decay time increases from ~4 d/mag to ~12 d/mag over the first ~15 d of the ~25 d superoutburst, as…

Astrophysics · Physics 2009-11-07 John K. Cannizzo

We report results of the eclipse mapping analysis of an ensemble of light curves of HT Cas. The fast response of the white dwarf to the increase in mass transfer rate, the expansion rate of the accretion disc at the same time, and the…

Solar and Stellar Astrophysics · Physics 2011-05-10 R. Baptista , B. Borges , V. Kolokotronis , O. Giannakis , C. J. Papadimitriou

We propose a simple explanation for the constant mean brightness observed between outbursts in dwarf novae. Secular changes in the total energy dissipation rate of the accretion disc brought about by variations in surface density,…

Astrophysics · Physics 2009-11-10 M. R. Truss , G. A. Wynn , P. J. Wheatley

A theoretical light curve is constructed for the quiescent phase of the recurrent nova U Scorpii in order to resolve the existing distance discrepancy between the outbursts (6 kpc) and the quiescences (14 kpc). Our U Sco model consists of a…

Astrophysics · Physics 2009-10-31 Izumi Hachisu , Mariko Kato , Taichi Kato , Katsura Matsumoto , Ken'ichi Nomoto

Results of UBVRIJHKLM photometry, VRI polarimetry and optical spectroscopy of a young star RW Aur A obtained during 2010-11 and 2014-16 dimming events are presented. During the second dimming the star decreased its brightness to \Delta V >…

We have used FUSE to obtain thirteen observations of the dwarf nova VW Hyi covering the period from the end of a superoutburst through the following normal outburst of the system. Here, we present the quiescent spectra. They contain at…

Astrophysics of Galaxies · Physics 2010-01-15 Knox S. Long , Boris T. Gaensicke , Christian Knigge , Cynthia S. Froning , Berto Monard

RW Aur is a young binary star that experienced a deep dimming in 2010-11 in component A and a second even deeper dimming from summer 2014 to summer 2016. We present new unresolved multi-band photometry during the 2014-16 eclipse, new…

Solar and Stellar Astrophysics · Physics 2016-09-20 I. Bozhinova , A. Scholz , G. Costigan , O. Lux , C. J. Davis , T. Ray , N. F. Boardman , K. L. Hay , T. Hewlett , G. Hodosán , B. Morton