6 papers
Accretion in Binary Systems with Slow Stellar Winds
Jesús A. Toalá, Emilio Tejeda, Diego A. Vasquez-Torres
Wind accretion in binary systems is commonly described using the Bondi-Hoyle-Lyttleton (BHL) formalism. However, its standard implementation fails in the slow-wind regime, where th…
The Influence of the Accretion Disc Structure on X-ray Spectral States in Symbiotic Binaries
Jesús A. Toalá, Diego A. Vasquez-Torres
Symbiotic stars are binary systems where a white dwarf (WD) accretes material from the wind of an evolved, late-type companion. X-ray-emitting symbiotic systems are classified into…
TiÄnguÄn ( Tau) as a binary system consisting of a Be-star and an accreting White Dwarf: opening a gate to understanding enigmatic Cas analogues
Jesús A. Toalá, Lidia M. Oskinova, Diego A. Vasquez-Torres
The analogues of Cassiopea are binary early type Be stars which are X-ray bright with hard thermal spectra. The nature of companions in these stars and mechanisms of their X-r…
Y Gem, a symbiotic star outshone by its asymptotic giant branch primary component
M. A. Guerrero, D. A. Vasquez-Torres, J. B. RodrÃguez-González +2
A considerable number of asymptotic giant branch (AGB) stars exhibit UV excess and/or X-ray emission that indicates a binary companion. AGB stars are so bright that they easily out…
Accretion onto WD 2226210, the central star of the Helix Nebula
S. Estrada-Dorado, M. A. Guerrero, J. A. Toalá +4
The central star of the Helix Nebula, WD 2226210 presents enigmatic hard X-ray emission and mid-IR excess. The latter has been attributed to a dusty disk or a cloud-like structu…
The impact of periastron passage on the X-ray and optical properties of the Symbiotic System R Aquarii
D. A. Vásquez-Torres, J. A. Toalá, A. Sacchi +4
Multi-epoch Chandra and XMM-Newton observations of the symbiotic system R Aquarii (R Aqr) spanning 22 yr are analysed by means of a reflection model produced by an accretion disc.…