Related papers: Nova Scorpii 1941 (V697 Sco): A Probable Intermedi…
We report optical spectroscopy and high speed photometry and polarimetry of the INTEGRAL source IGRJ14536-5522 (=Swift J1453.4-5524). The photometry, polarimetry and spectroscopy are modulated on an orbital period of 3.1564(1) hours.…
We report high-precision observations of the linear polarization of the F1$\,$III star $\theta$ Scorpii. The polarization has a wavelength dependence of the form expected for a rapid rotator, but with an amplitude several times larger than…
The ``Neptunian ridge'' is a recently identified peak in the frequency of planets with sizes between that of Neptune and Saturn orbiting their host stars with periods between 3 and 6 days (A. Castro-Gonz\'alez et al. 2024). These planets…
New and archived observations of VW Hyi in outburst show the occasional presence of optical Dwarf Nova Oscillations (DNOs) over the range of 18 - 40 s. There is a rapid increase in period near the end of outburst, at the same time that the…
CoRoT-2a is a young (about 0.5 Gyr) G7V star accompanied by a transiting hot-Jupiter, discovered by the CoRoT satellite (Alonso et al. 2008; Bouchy et al. 2008). An analysis of its photospheric activity, based on spot modelling techniques…
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 present the first results of a photometric survey of poorly studied nova remnants in the Northern Hemisphere. The main results are as follows: DM Gem shows a modulation at 0.123 d (probably linked to the orbit) and rapid variations at…
We present and analyze optical photometry and high resolution SALT spectra of the symbiotic recurrent nova V3890 Sgr at quiescence. The orbital period, P=747.6 days has been derived from both photometric and spectroscopic data. Our…
SRGt 062340.2-265751, a cataclysmic variable identified by SRG/eROSITA thanks to its significant X-ray variability, remains poorly characterised despite the multi-wavelength follow-up. We present spectral and timing analyses from the first…
Intermediate polars are members of the cataclysmic variable binary stars. They are characterized by a moderately magnetized white dwarf accreting matter from a cool main-sequence companion star. In many cases, this accretion gives rise to a…
We present analyses of an Intermediate Polar, IGR J15094-6649, based on the archival optical data obtained from the Transiting Exoplanet Survey Satellite (TESS) and X-ray data obtained from the Suzaku, NuSTAR, and Neil Gehrels Swift…
The only well-studied red nova progenitor (V1309 Sco) was a contact binary with a 1.4-day period. The prospects for searching for similar systems, as well as stellar merger candidates in general, are explored in this work. The photospheric…
We present spectroscopy and orbital periods Porb of four relatively little-studied cataclysmic variable stars. The stars and their periods are: AF Cam, Porb = 0.324(1) d (the daily cycle count is slightly ambiguous); V2069 Cyg (= RX…
We present multi-color light curves and optical spectra of V1280 Scorpii obtained from 2007 to 2012. It is shown that V1280 Sco is the extremely slow nova and the mass of white dwarf appears to be $\sim$ 0.6 M$\odot$ or lower. Blue-shifted…
We present a preliminary analysis of the photospheric activity of CoRoT-Exo-2a, a young G7V star accompanied by a transiting hot Jupiter recently discovered by CoRoT. We apply spot modelling techniques developed for the analysis of the Sun…
We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density $<$ 0.2 g/cm$^3$ on a 105-day prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the Antarctic telescope…
Aims: We determine the nature of the intermediate polar candidates XSS J00564+4548, IGR J17195-4100, and XSS J12270-4859. Methods: Pointed RXTE observations searched for intermediate polar characteristics in these candidate systems.…
We have conducted timing observations of the eclipsing millisecond binary pulsar PSR~B1957+20, extending the span of data on this pulsar to more than five years. During this time the orbital period of the system has varied by roughly…
Results from spectroscopic observations of the Intermediate Polar (IP) EX Hya in quiescence during 1991 and 2001 are presented. Spin-modulated radial velocities consistent with an outer disc origin were detected for the first time in an IP.…
Short time scale photometric properties of eight faint Cataclysmic Variable (CV) stars are presented. Nova Carinae 1895 (RS Car) has a photometric modulation at 1.977 h which could be either an orbital or a superhump period. Nova Carinae…