Transient jets in the symbiotic prototype Z Andromedae
Authors:
A. Skopal, T. Pribulla, J. Budaj, A.A. Vittone, L. Errico, M. Wolf, M. Otsuka, M. Chrastina, Z. Mikulasek
Image & caption:
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Image caption::
Top panels show the U,B,V light curves of Z And covering its two major eruptions (2000, 2006). Arrows indicate times of spectroscopic observations. Absence of jets is denoted by "x". The lower block of panels displays the jet emission components, S- and S+, in the H-alpha line profile (left), evolution of the jet radial velocities (middle) and a short-term variability in the optical continuum, which developed during the transient period of the jet launching (right).
Description:
For the first time we detected collimated bipolar jets from the symbiotic prototype Z And during its 2006 outburst. Their presence was transient, being detected to the end of 2006. We monitored the
outburst with optical high-resolution spectroscopy and multicolor UBVR photometry. During the optical maximum, rapid photometric variations with ~0.06 mag on the timescale of hours developed. Simultaneously, high-velocity satellite components appeared on both sides of the H-alpha and H-beta emission line profiles. Spectral properties of these satellite emissions indicated ejection of bipolar jets collimated within an average opening angle of 6 degrees. They were launched at a velocity of ~5000 km/s, asymmetrically with the red/blue velocity ratio of 1.2-1.3. We estimated average outflow rate via jets to ~2E-6 solar masses per year. Evolution in the rapid photometric variability and asymmetric ejection of jets around the optical maximum can be explained by a disruption of the inner parts of the disk caused by radiation-induced warping of the disk.
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