Related papers: RX J1643.7+3402 : a new bright cataclysmic variabl…
Photometric and spectroscopic observations reveal the Sloan Digital Sky Survey cataclysmic variable SDSS J132723.39+652854.2 to be a likely SW Sex star with an orbital period of P = 3.28 hours. The Sloan Digital Sky Survey spectrum shows…
Cataclysmic variables (CVs) that have evolved past the period minimum during their lifetimes are predicted to be systems with a brown dwarf donor. While population synthesis models predict that around $\approx 40-70\%$ of the Galactic CVs…
The RApid Temporal Survey (RATS) is a survey to detect objects whose optical intensity varies on timescales of less than ~70 min. In our pilot dataset taken with the INT and the Wide Field Camera in Nov 2003 we discovered nearly 50 new…
High speed photometry of the helium-transferring binary ES Cet - taken over a two-year period (2001 October - 2003 October) - shows a very stable photometric period of 620.211437 +/- 0.000038 s, with a tentative indication of curvature in…
We present time-resolved spectroscopy and photometry of SDSS J100658.40+233724.4, which we have discovered to be an eclipsing cataclysmic variable with an orbital period of 0.18591324 days (267.71507 min). The observed velocity amplitude of…
We present the results of our analysis of new optical, ultraviolet (UV) and X-ray observations of a highly variable source $-$ AX J1549.8$-$5416. Both the detection of several fast rise, exponential decay outbursts in the optical light…
We report the discovery of a new variable star, called S 10947 Aql, as the likely optical counterpart of RX J2009.8+1557. The optical variability pattern as well as the detected X-ray emission suggest that it is a chromospherically active…
Images recorded with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South are combined with archival images from other facilities to search for variable stars in the southern portion of the nearby disk galaxy NGC 247. Fifteen new…
The variable star V1129 Cen is classified in the GCVS as being of $\beta$ Lyr type. Unusual for such stars, it exhibits outbursts roughly once a year, lasting for $\sim$40 days. For this reason, a relationship to the dwarf novae has been…
The enigma source, RX J1856.5-3754, is one of the so-called dim thermal neutron stars. Two puzzles of RXJ1856.5-3754 exist: (1) the observational X-ray spectrum is completely featureless; (2) the UV-optical intensity is about seven times…
We present the TESS observations of CRTS J110014.7+131552, SDSS J093537.46+161950.8, and [PK2008] HalphaJ130559. Among them, a superoutburst is observed in CRTS J110014.7+131552 which is associated with the precursor outburst, where…
A radial velocity study is presented of the cataclysmic variable V378 Pegasi (PG 2337+300). It is found to have an orbital period of 0.13858 +/- 0.00004 d (3.32592 +/- 0.00096 hours). Its spectrum and long-term light curve suggest that V378…
We report the discovery of a new AM Herculis binary (polar) as the optical counterpart of the soft X-ray source RX J1724.0+4114 detected during the ROSAT all-sky survey. The magnetic nature of this V~17 mag object is confirmed by…
We have identified two moderately bright, rapidly variable transients in new and archival X-ray data near the Galactic center. Both objects show strong, flaring variability on timescales of tens to thousands of seconds, evidence of N_H…
We present the results of our study of ASASSN-14dx, a previously known but poorly characterised cataclysmic variable (CV). The source was observed as part of an ongoing high-time-resolution photometric survey of CVs, which revealed that, in…
We analyse public domain time-series photometric observations of 30 known and candidate binary post-AGB stars for measuring pulsation and orbital periods. We derive periodicities for 17 stars for the first time in the literature. Besides…
On the basis of spectrophotometric observations we reconstruct the accretion disk of the eclipsing novalike cataclysmic variable RW Tri in the wavelength region 3600-7000 A. We find a radial temperature profile that is, on average,…
Variability on all time scales between seconds and decades is typical for cataclysmic variables (CVs). One of the brightest and best studied CVs is TT Ari, a nova-like variable which belongs to the VY Scl subclass, characterized by…
RX J0720.4-3125 is the third brightest neutron star in the soft X-ray sky and has been a source of mystery since its discovery, as its long 8-s period separates it from the population of typical radio pulsars. Three models were proposed for…
We report the discovery of a new 13th magnitude variable in Cassiopeia close to the variable KP Cas. Analysis of 6 days of intensive photometry shows a regular, near sinusoidal modulation with an amplitude of 0.024 magnitudes and a period…