Discovery of collimated ejection from the symbiotic binary BF Cygni
Authors:
A. Skopal, N.A. Tomov, M.T. Tomova
Image & caption:
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Image caption::
Figure 1. Top panel shows the UBVRI light curves of BF Cyg covering its 2006-12 active phase. Arrows indicate times of our spectroscopic observations. The lower panels display a comparison of the Hα and Hβ line profiles from the beginning of the outburst and in 2012. The filled curves represent the jet emission components. Fluxes are in 10−13 erg cm−2 s−1 Å−1.
Description:
Detection of collimated ejection from white dwarfs in symbiotic binaries is very rare. To date, for almoust 300 known symbiotic stars, its signature in the optical spectra has only been recorded for four objects (MWC 560, Hen-3-1341, StHa-190 and Z And). We present the first detection of highly-collimated bipolar ejection from the symbiotic binary BF Cyg, which developed during its current active phase, from 2009. We monitored the outburst spectroscopically (high-resolution spectra have been carried out at the Rozhen Observatory, BAS) and photometrically (multicolour UBVRI photometry has been carried out with telescopes of AI SAS). A maximum of jets was indicated during 2012, when the ejected mass was collimated within the opening angle < 15 degrees and generated the light energy almoust a factor of 10 higher than our Sun. Formation of the collimated ejection a few years after the eruption and its evolution on a timescale of years at a constant optical brightness contributes to our better understanding the accretion process during the active phases of symbiotic stars.
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