Related papers: High-Level Magnetic Activity on a Low-Mass Close B…
New multiband CCD photometry is presented for the eclipsing binary GW Gem; the $RI$ light curves are the first ever compiled. Four new minimum timings have been determined. Our analysis of eclipse timings observed during the past 79 years…
The first photometric light curve investigation of the NSVS 8294044, V1023 Her, and V1397 Her binary systems is presented. We used ground-based observations for the NSVS 8294044 system and Transiting Exoplanet Survey Satellite (TESS) data…
Stellar activity cycles reveal continuous relaxation and induction of magnetic fields. The activity cycle is typically traced through the observation of cyclic variations in total brightness or Ca H&K emission flux of stars, as well as…
We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 10992733 and KIC 5632781 undergo total eclipses while KIC 10026136 reveals partial eclipses. The…
High-accuracy multicolor light curves of the binary system HD 189733, which contains an exoplanet, are analyzed. We have determined the radii of the star and the planet in the binary system, as well as the orbital inclination. The…
The starspots on the surface of many chromospherically active binary stars concentrate on long--lived active longitudes separated by 180 degrees. The activity shifts between these two longitudes, the "flip-flop" events, have been observed…
Inspired by the discovery of the red nova V1309 Sco (Nova Scorpii 2008) and the fact that its progenitor was a binary system with a rapidly decreasing orbital period, we have searched for period changes in OGLE binary stars. We have…
CCD photometric observations in VRI colors and spectroscopic observations of the newly discovered eclipsing binary GSC 2314-0530 (NSVS 6550671) with dMe components and very short period of P=0.192636 days are presented. The simultaneous…
We use high-resolution relativistic MHD simulations coupled with a radiative transfer code to compute multiwavelength afterglow light curves of magnetized ejecta of gamma-ray bursts interacting with a uniform circumburst medium. The aim of…
This study of SDSS0804 is primarily concerned with the double-hump shape in the light curve and its connection with the accretion disk in this bounce-back system. Time-resolved photometric and spectroscopic observations were obtained to…
Analysis of 28 years of OGLE project data for the 0.404 day period binary OGLE BLG ELL-006503 (V1231 Sco) shows a superposition of tidal-interaction variations of about 0.07 magnitude in the I-band onto a time-scale 5-10 year, 0.15-0.17…
KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 d that is below the short-period limit ($\sim$0.22 d) of the period distribution for contact binaries. The {\it Kepler} light curve of the system exhibits…
The first photometric analysis of V811 Cep was carried out. The first complete light curves of V, R and I bands are given. The analysis was carried out by Wilson-Devinney (W-D) program, and the results show that V811 Cep is a median-contact…
Eclipsing binaries are instrumental to our understanding of fundamental stellar parameters. With the arrival of ultra-wide cameras and large area photometric monitoring programs, numerous eclipsing binaries systems have been reported…
Low mass ratio contact binary systems are more likely to have unstable orbits and potentially merge. In addition, such systems exhibit characteristics such as starspots and high energy emissions (UV) suggestive of chromospheric and magnetic…
We present multicolour photometry and modelling of the active eclipsing binary star V405 And. The components of 0.2 and 0.5 solar masses are just below and above the theoretical limit of the full convection, that is thought to be around 0.3…
We analyze the surface structure of the planet host star CoRoT-2a using a consistent model for both the `global' (i.e., rotationally modulated) lightcurve and the transit lightcurves, using data provided by the CoRoT mission. Selecting a…
We present the results of our study of the eclipsing binary systems CSS J112237.1+395219, LINEAR 1286561 and LINEAR 2602707 based on new CCD $B$, $V$, $R_c$ and $I_c$ complete light curves. The ultra-short period nature of the stars…
Ground-based observations of exoplanet eclipses provide important clues to the planets' atmospheric physics, yet systematics in light curve analyses are not fully understood. It is unknown if measurements suggesting near-infrared flux…
We present a brief summary of observations of the transiting extrasolar planet, HD 209458 b, designed to detect the secondary eclipse. We employ the method of `occultation spectroscopy', which searches in combined light (star and planet)…