4 research outputs found
The origin of the supersoft X-ray--optical/UV flux anticorrelation in the symbiotic binary AG Draconis
AG Draconis produces a strong supersoft X-ray emission.The X-ray and
optical/UV fluxes are in a strict anticorrelation throughout the active and
quiescent phases. The aim of this contribution is to identify the source of the
X-ray emission and reveal the nature of the observed flux anticorrelation. For
this purpose we model the X-ray and UV observations with XMM-Newton, far-UV
spectroscopy from FUSE, low- and high-resolution IUE spectra and
optical/near-IR spectroscopic and/or photometric observations. Our analysis
showed that the supersoft X-ray emission is produced by the white dwarf
photosphere. The X-ray and far-UV fluxes make it possible to determine its
temperature unambiguously. The supersoft X-ray--optical/UV flux anticorrelation
is caused by the variable wind from the hot star. The enhanced hot star wind
gives rise to the optical bursts by reprocessing high-energy photons from the
Lyman continuum to the optical/UV.Comment: 9 pages, 2 figures, 3 tables. Submitted to AA on 25/11/2008, revised
on 27/05/200
Tau Ori and Tau Lib: Two New Massive Heartbeat Binaries
We report the discovery of two massive eccentric systems with BRITE data,
tau Ori and tau Lib, showing heartbeat effects close to the periastron passage. τ Lib
exhibits shallow eclipses that will soon vanish due to the apsidal motion in the
system. In neither system, tidally excited oscillations were detected