Related papers: Formation of a disk structure in the symbiotic bin…

We present the results of a high accuracy ($\sigma \approx 0.005%$) polarization monitoring of the Be Star Achernar that was carried out between July 7th and November 5th, 2006. Our results indicate that, after a near quiescent phase from…

In the optical, the spectrum of symbiotic binaries consists of contributions from the cool giant, symbiotic nebula and the hot star. Strong emission lines are superposed on the continuum. In this paper we introduce a simple method to…

AG Dra is a symbiotic variable consisting of a metal poor, yellow giant mass donor under-filling its Roche lobe, and a hot accreting white dwarf, possibly surrounded by an optically thick, bright accretion disk which could be present from…

The author presents the results of Berkeley-Illinois-Maryland (BIMA) array interferometric observations in the CO J=1-0 line toward X Her and EP Aqr, the semiregular pulsating stars with a composite CO line profile, and also reports finding…

Many post-AGB star binaries are observed to have relatively high orbital eccentricities (up to 0.6). Recently, AC Her was observed to have a polar-aligned circumbinary disk. We perform hydrodynamic simulations to explore the impact of a…

Photometry of the unique pre-main sequence binary system KH 15D is presented, spanning the years 2005-2010. This system has exhibited photometric variations and eclipses over the last 50 years caused by a precessing circumbinary disk.…

We describe the first results from a program of multi-wavelength monitoring of symbiotic binary stars in outburst. The prototypical symbiotic star Z Andromedae was observed extensively at radio, optical, far-UV, and X-ray wavelengths during…

AK~Sco stands out among pre-main sequence binaries because of its prominent ultraviolet excess, the high eccentricity of its orbit and the strong tides driven by it. AK Sco consists of two F5 type stars that get as close as 11R$_*$ at…

X-ray polarimetry is a fine tool to probe the accretion geometry and physical processes operating in the proximity of compact objects, black holes and neutron stars. Recent discoveries made by the Imaging X-ray Polarimetry Explorer put our…

In a high-mass X-ray binary (HMXB) a massive star interacts with a neutron-star or black-hole companion in various ways. The gravitational interaction enables the measurement of fundamental parameters such as the mass of both binary…

Results of the study of the symbiotic binary Z And during its recent active phase 2000 -- 2010 when it experienced a series of six optical outbursts are presented. High-resolution spectra obtained during the first and fourth outburst, which…

Z Andromedae is a prototype of classical symbiotic variable stars. It is characterized by alternating of quiescent and active stages, the later ones are accompanied by changes in both photometry and spectral characteristics of this object.…

Star-forming regions, characterized by dense environments, experience frequent encounters that significantly influence binary systems, leading to their hardening, softening, or ionization. We extend the Hut \& Bahcall formalism to derive an…

We report on \textit{NuSTAR} observations of the well-known wind-accreting X-ray pulsar \source\ during a strong spin-up episode that took place in January-March 2019. A high luminosity of the source in a most recent observation allowed us…

A cold neutral and extremely dim accretion disk may be present as a remnant of a past vigorous activity around the black hole in our Galactic Center (GC). Here we discuss ways to detect such a disk through its interaction with numerous…

Young eruptive stars such as EXors undergo dramatic accretion outbursts characterized by sudden optical brightenings, yet the underlying physical mechanism remains uncertain. We present high-resolution Atacama Large Millimeter/submillimeter…

We present the analysis of publicly available NuSTAR, Suzaku and XMM-Newton observations of the symbiotic recurrent nova T CrB covering the 2006.77-2022.66 yr period. The X-ray spectra are analysed by adopting a model that includes a…

Symbiotic X-ray binaries (SyXBs) comprise a rare class of low-mass X-ray binaries. We study the Galactic SyXBs, which we consider as detached binaries composed of low-mass giants and wind-fed neutron star companions, by simulation of the…

We show that the inner regions of a cool accretion disk in an X-ray binary can transform into an advective, ion supported accretion flow (an optically thin ADAF, here called ISAF), through events involving only the known properties of the…

R Aqr is a symbiotic binary system consisting of a mira variable, a hot companion with a spectacular jet outflow, and an extended emission line nebula. We have used R Aqr as test target for the visual camera subsystem ZIMPOL, which is part…