Related papers: UX Monocerotis as a W Serpentis binary
We describe the discovery of a 0.68+0.52 solar mass eclipsing binary (EB) with an 8.4-day orbital period, found through a systematic search of ten fields of the Trans-atlantic Exoplanet Survey (TrES). Such long-period low-mass EBs…
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…
Analysis of new radial velocity measurements of the active giant PZ Mon is presented. Only in 2015 was reported that PZ Mon may be classified as RS CVn giant. At the same time was discovered the variability of radial velocity. However, lack…
V444 Cyg is a WN5+O6 V eclipsing binary system that exhibits a secular variation in its orbital period due to the loss of matter from the Wolf-Rayet star through its powerful stellar wind. This makes it possible to obtain a dynamical…
Radial velocities analysis based on high-resolution spectra, obtained in the H$\alpha$ region and low resolution spectra obtained in the region 4420-4960\AA together with radial velocities, taken from other published sources allow us to…
UW Coronae Borealis (UW CrB) is a low mass X-ray binary that shows both Type 1 X-ray and optical bursts, which typically last for 20 s. The system has a binary period of close to 2 hours and is thought to have a relatively high inclination…
We present phase resolved optical spectroscopy and X-ray timing of the neutron star X-ray binary EXO 0748-676 after the source returned to quiescence in the fall of 2008. The X-ray light curve displays eclipses consistent in orbital period,…
The complexity of composite spectra of close binary star system makes study of the spectra of their component stars extremely difficult. For this reason there exists very little information on the photospheric chemical composition of stars…
Context. Ultracompact X-ray binaries (UCXBs) typically consist of a white dwarf donor and a neutron star or black hole accretor. The evolution of UCXBs and very low mass ratio binaries in general is poorly understood. Aims. We investigate…
We model the secular evolution of a star's orbit when it has a nearby binary system. We assume a hierarchical triple system where the inter-binary distance is small in comparison with the distance to the star. We show that the major secular…
We present an X-ray timing analysis of the transient X-ray binary MXB 1658-298, using data obtained from the RXTE and XMM-Newton observatories. We have made 27 new mid eclipse time measurements from observations made during the two…
Double-lined eclipsing binaries allow accurate and direct determination of fundamental parameters such as mass and radius for each component, and they provide important constraints on the stellar structure and evolution models. In this…
Ultra-luminous X-Ray Objects are off-nucleus point sources with $L_X=10^{39}$-$10^{41}$ erg/s but the nature of such systems are largely unidentified. Here we report a 2.1 hour period observed in a Chandra ACIS observation for ULX M51 X-7,…
The ultraluminous x-ray source (ULX) in the galaxy M82 has been identified as a possible intermediate-mass black hole. We have found that the x-ray flux from M82 is modulated with a peak-to-peak amplitude corresponding to an isotropic…
We describe new optical photometric and spectroscopic observations of the semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg I absorption at secondary maximum indicates the presence of cool material in the outer…
The post-main sequence eclipsing binary NN Serpentis was recently announced as the potential host of at least two massive planetary companions. In that work, the authors put forward two potential architectures that fit the observations of…
We have analyzed all archival RXTE/PCA monitoring observations of the ultraluminous X-ray source (ULX) M82 X-1 in order to study the properties of its 62 day X-ray period (Kaaret & Feng 2007). Based on its high coherence it has been argued…
We aim at constraining evolutionary models at low mass and young ages by identifying interesting transiting system members of the nearest OB association to the Sun, Upper Scorpius, targeted by the Kepler mission. We produced light curves…
We report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541 Cyg (P = 15.34 days, e = 0.468). Using these observations together with existing measurements we…
We used recently produced Solar System ephemerides, which incorporate two years of ranging observations to the MESSENGER spacecraft, to extract the secular orbital elements for Mercury and associated uncertainties. As Mercury is in a stable…