Related papers: HS Hya about to turn off its eclipses

We report 90 new observations of three post common envelope binaries at primary eclipse spanning between December 2018 to February 2022. We combine recent primary eclipse timing observations with previously published values to search for…

This study continues our in-depth investigation of total-eclipse W Ursae Majoris-type contact binaries by analyzing eight new systems, complementing our previous work. Multiband $BVR_cI_c$ photometric data were acquired through ground-based…

We present an analysis of the early Kepler observations of the previously discovered transiting planet HAT-P-7b. The light curve shows the transit of the star, the occultation of the planet, and the orbit phase-dependent light from the…

We present the discovery and the very first analysis of four stellar systems showing two periods of eclipses, that are the objects classified as doubly eclipsing systems. Some of them were proved to orbit each other thanks to their…

We utilize multi-dimensional simulations of varying equatorial jet strength to predict wavelength dependent variations in the eclipse times of gas-giant planets. A displaced hot-spot introduces an asymmetry in the secondary eclipse light…

We report the identification of the bright (V${\sim}13.3$ mag) star FY Sct as a long period detached eclipsing binary using a combined ASAS-SN and ASAS light curve spanning 2000-2018. The orbital period is P${\sim}2.57$ years and the…

In 2002, 2004, and 2017 we conducted high precision CCD photometry observations of the eclipsing binary system AS~Cam. By the analysis of the light curves from 1967 to 2017 (our data + data from the literature) we obtained photometric…

We present the results of our monitoring of the halo black-hole soft X-ray transient (SXT) XTE J1118+480 during its decline to quiescence. The system has decayed 0.5 mags from December 2000 to its present near quiescent level at R=18.65…

DI Herculis is an eclipsing binary famous for a longstanding disagreement between theory and observation of the apsidal precession rate, which was resolved when both stars were found to be severely misaligned with the orbit. We used data…

The BVR photometric light curves of the eclipsing binary BD And were obtained in 2008 and 2009. We estimated the mass ratio of the system as 0.97 and the photometric solutions were derived. The results show that BD And is a detached binary…

The magnetic cataclysmic variable HU Aquarii displayed pronounced modulations of its eclipse timing. These were intensively modeled and discussed in recent years in the framework of planets orbiting the binary or the Applegate effect. No…

We study iPTF14hls, a luminous and extraordinary long-lived Type II supernova, which lately has attracted much attention and disparate interpretation. We present new optical photometry that extends the light curves until more than 3 yr past…

We report the discovery with TESS of a remarkable quadruple star system with a 2+1+1 configuration. The two unique characteristics of this system are that (i) the inner eclipsing binary (stars Aa and Ab) eclipses the star in the outermost…

We analyzed period changes of the high-amplitude Delta Scuti variable star CSS_J102714.3+205943 for about 20 years, utilizing data from the automated sky surveys along with our own observations. With the help of the O-C diagram, we found…

We describe a newly-discovered detached M-dwarf eclipsing binary system, the fourth such system known. This system was first observed by the TrES network during a long term photometry campaign of 54 nights. Analysis of the folded light…

We report on follow-up spectroscopy and photometry of the cataclysmic variable candidate HS0907+1902 selected from the Hamburg Quasar Survey. B, V, and R photometry obtained during the first observed outburst of HS0907+1902 (V~13) reveals…

High-resolution spectroscopy and speckle interferometry reveal the young star HD 86588 as a quadruple system with a 3-tier hierarchy. The 0.3" resolved binary A,B with an estimated period around 300 years contains the 8-year pair Aa,Abc…

Time-domain spectroscopy of the classical accreting T Tauri star, TW Hya, covering a decade and spanning the far UV to the near-infrared spectral regions can identify the radiation sources, the atmospheric structure produced by…

The recurrent nova IM Nor is found to have an orbital period of 2.462 h, shown by periodic dips in brightness. This is only the second recurrent nova known to have such a short period. We interpret the light curve as largely produced by a…

As a continuation of our previous studies in 2007 and 2008, new photometric observations of the T Tauri star TW Hya obtained by the MOST satellite and the ASAS project over 40 days in 2009 with temporal resolution of 0.2 days are presented.…