Evidence for bipolar jets from the optical spectra of the prototypical symbiotic star Z Andromedae

Abstract

We have studied optical spectra of the symbiotic star Z And, obtained during its latest outburst started in April 2006, with the aim of finding changes in the spectrum yielding clues to the nature of the hot component and its outbursts. The spectroscopic observations of Z And have been made using the 1.5-meter telescope at the Tartu Observatory, Estonia, and processed in a standard way. We have found high velocity satellites to the hydrogen Balmer emission lines. Starting from July 30, 2006, weak additional emission components at velocities of about +/-1150 km/s were detected. Their appearance near the outburst maximum and similarity to the emission features in another symbiotic star Hen 3-1341 imply fast collimated outflows from the hot component of Z And. This finding is consistent with the earlier results by several authors that symbiotic stars can emit bipolar jets at certain stages of their outbursts. A significant decrease in the temperature of the hot component in initial stages of the outburst was detected by the disappearance of the high excitation emission line from the spectrum.

4 pages, 6 figures, accepted for publication by A&A Letters

References in corpus (7)

• On Why Disks Generate Magnetic Towers and Collimate Jets
• A "Combination Nova" Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability
• Discovery of a Magnetic White Dwarf in the Symbiotic Binary Z Andromedae
• A radio jet in the prototypical symbiotic star Z And?
• Structure of the hot object in the symbiotic prototype Z And during its 2000-03 active phase
• Discovery of a bipolar and highly variable mass outflow from the symbiotic binary StHa 190
• Bipolar jets growth and decline in Hen 3-1341: a direct link to fast wind and outburst evolution

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• The spectroscopic evolution of the symbiotic star AG Draconis. I.The O VI Raman, Balmer, and helium emission line variations during the outburst of 2006-2008
• Repeated transient jets from a warped disk in the symbiotic prototype Z And: A link to the long-lasting active phase
• Broad absorption line symbiotic stars: highly ionized species in the fast outflow from MWC 560
• Formation of a disk-structure and jets in the symbiotic prototype Z And during its 2006-2010 active phase
• V4141 Sgr: Outflows and repeated outbursts
• A collimated wind interpretation for the spectral variability of Z And during its major 2006 eruption