Related papers: AM CVn -- System Parameters and Gravitational Wave…

A new ephemeris, period change analysis and light curve modeling of the W UMa-type eclipsing binary BF Pav are presented in this study. Light curves of the system taken in BVRI filters from two observatories in Australia and Argentina were…

We report discovery and characterization of a main-sequence G star orbiting a dark object with mass $1.90\pm 0.04 M_{\odot}$. The system was discovered via Gaia astrometry and has an orbital period of 731 days. We obtained multi-epoch RV…

We present an improved dynamical model of the X-ray binary and microquasar XTE J1550-564 based on new moderate-resolution optical spectroscopy and near-infrared photometry. By combining our new radial velocity measurements with previous…

ASAS photometric observations of LS 1135, an O-type SB1 binary system with an orbital period of 2.7 days, show that the system is also eclipsing. This prompted us to re-examine the spectra used in the previously published spectroscopic…

The estimate of the change rate of the solar gravitational parameter $\mathrm{d}(GM_{\odot})/\mathrm{d}t$ is obtained from processing modern positional observations of planets and spacecraft. Observations were processed and parameters were…

We present calibrated photometry and time-resolved spectroscopy of the cataclysmic variable GZ Cnc. Radial velocities of the H-alpha emission line reveal an orbital period of 0.08825(28) d, or 2.118(07) h, placing the system at the lower…

The properties of the aperiodic brightness variability for the dwarf nova HL CMa are considered. The variability of the system HL CMa is shown to be suppressed at frequencies above $7\times10^{-3}$Hz. Different variability suppression…

We observed the field of the Fermi source 3FGL J0838.8-2829 in optical and X-rays, initially motivated by the cataclysmic variable (CV) 1RXS J083842.1-282723 that lies within its error circle. Several X-ray sources first classified as CVs…

Primordial gravitational waves (GWs) with frequencies > 10^{-15} Hz contribute to the radiation density of the Universe at the time of decoupling of the cosmic microwave background (CMB). The effects of this GW background on the CMB and…

When accretion temporarily ceases in the polar AM Her, the emission line profiles are known to develop several distinct components, whose origin remains poorly understood. The new low-state spectra reported here have a more favorable…

The gamma-ray binary 1FGL J1018.6-5856 consists of an O6V((f)) type star and an unknown compact object, and shows orbitally modulated emission from radio to very high energy gamma rays. The X-ray light curve shows a maximum around the same…

We derive precise system parameters for the pre-cataclysmic binary, NN Ser. From light curve fitting we find an orbital inclination of i = 89.6 +/- 0.2 deg. From the HeII absorption line we find K_{WD}= 62.3 +/- 1.9 km/s. The…

We report the discovery of ATLAS J101342.5-451656.8 (hereafter ATLAS J1013-4516), an 8.56 minute orbital period mass transferring AM Canum Venaticorum binary with mean Gaia magnitude G=19.51. The system was identified via periodic…

Excitation of radial oscillations in population I (X=0.7, Z=0.02) red supergiants is investigated using the solution of the equations of radiation hydrodynamics and turbulent convection. The core helium burning stars with masses 8M_odot <=…

We present the first calculations of the gravitational radiation produced by nonaxisymmetric dynamical instability in a rapidly rotating compact star. The star deforms into a bar shape, shedding $\sim 4\%$ of its mass and $\sim 17\%$ of its…

Calculations of stellar evolution up to the early white dwarf stage were carried out for stars with mass on the main sequence $M_0=0.82M_\odot$, $0.85M_\odot$, $0.9M_\odot$ and with initial abundances of helium and heavier elements $Y=0.25$…

Gravitational waves emitted by asymmetric rotating neutron stars are the primary targets of continuous gravitational-wave searches. Neutron stars in binary systems are particularly interesting due to the potential for non-axisymmetric…

The presence of mean motion resonances (MMRs) complicates analysis and fitting of planetary systems observed through the radial velocity (RV) technique. MMR can allow planets to remain stable in regions of phase space where strong…

Pulsation period decrease during the initial stage of the thermal pulse in the helium-burning shell of the Mira-type variable T UMi is investigated with numerical methods of stellar evolution and radiation hydrodynamics. To this end, a grid…

The AM CVn systems are a class of He-rich, post-period minimum, semi-detached, ultra-compact binaries. Their long-term light curves have been poorly understood due to the few systems known and the long (hundreds of days) recurrence times…