We present the development of the collimated bipolar jets from the symbiotic prototype Z And that appeared and disappeared during its 2006 outburst. We monitored the outburst with the optical high-resolution spectroscopy and multicolor U BV R C photometry. In 2006 July Z And reached its historical maximum at U ∼ 8.0. After ∼1 mag decline in mid-August, it kept its brightness at a high level of U ∼ 9 up to 2007 January. During this period, rapid photometric variations with ∆m ∼ 0.06 mag on the timescale of hours developed. Simultaneously, high-velocity satellite components appeared on both sides of the Hα and Hβ emission line profiles. Their presence was transient, being detected to the end of 2006. They were launched asymmetrically with the red/blue velocity ratio of 1.2-1.3. From about mid-August onward they became symmetric at ∼ ± 1200 km s −1 , reducing the velocity to ∼ ± 1100 km s −1 at their disappearance. Spectral properties of these satellite emissions indicated the ejection of
Aims. To investigate structure of the hot object in the symbiotic prototype Z And during its major 2000−03 active phase. Methods. Analysis of the far ultraviolet, optical low-and high-resolution spectroscopy and UBVR photometry. Reconstruction of the spectral energy distribution (SED) during the outburst. The Raman scattering process. Results. At the initial stages of the outburst the hot object was characterized by the two-temperature spectrum (a warm stellar radiation and a strong nebular emission) with signatures of a mass-outflow at moderate (∼100−200 km s −1 ) and very high (≈1000−2000 km s −1 ) velocities. The corresponding structure of the hot object consists of an optically thick, slowly-expanding disk-like material encompassing the accretor at the orbital plane and a fast optically thin wind over the remainder of the star. The disk-like shell persisted around the central star until 2002 August as was indicated by the eclipse effect. Then, a significant dilution of the optically thick material and evolution of a fast wind from the hot star, concentrated more at the orbital plane, were detected. A striking similarity of [Fe vii] λ6087 and Raman λ6825 profiles at/after the dilution of the disk suggests their origin within the interaction zone where the winds from the binary components collide.
Abstract. New extensive multicolour photoelectric photometry, performed since 1994, is presented. 17 moreor-less complete light curves were obtained and analyzed. The Wilson-Devinney code applied to the BVRI light curves without the maculation effect together with published spectroscopic mass ratio and semi-major axis yielded new absolute parameters of the eclipsing pair: m1 = 1.10 M , m2 = 0.66 M , R1 = 1.16 R , R2 = 0.63 R , a = 3.107 R and the orbital inclination i = 80.9• . The observed orbital period changes are conclusively explained by the mutual action of the third body in the system (P3 = 30 years) and the maculation effects. Simultaneous analysis of the period changes and the visual brightness excludes the possibility of their explanation by Applegate's mechanism. The differences in the maxima heights caused by the maculation exhibit variations with the period of 709± 10 days. The distance to the system d = 86± 5 pc determined from the absolute dimensions and luminosities of the components is larger than the Hipparcos astrometric value d = 66 ± 6 pc.
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