EDP Sciences
Free access
Volume 401, Number 3, April III 2003
Page(s) L17 - L20
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20030332

A&A 401, L17-L20 (2003)
DOI: 10.1051/0004-6361:20030332


Discovery of the eclipse in the symbiotic binary Z Andromedae

A. Skopal

Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica, Slovakia
(Received 10 February 2003 / Accepted 6 March 2003)

Our photometric observations of the symbiotic binary Z And during its recent (2000-2003) active phase revealed a minimum in the UB and V light curves (LC) at the position of the inferior conjunction of its cool component (the orbital phase $\varphi = 0$). This fact and the behaviour of colour indices suggest that the minimum was due to the eclipse of the active hot object by the red giant. Physically plausible fit of the eclipse profile and a precise analysis of the spectral energy distribution (SED) in the ultraviolet continuum suggest a disk-like structure for the hot object during active phases. The present knowledge of fundamental parameters of the system limits the orbital inclination  i to  $76^{\circ}{-}90^{\circ}$. The presence of the Rayleigh attenuated far-UV continuum at  $\varphi \sim 0$ during quiescent phase confirms the very high inclination of the Z And orbit.

Key words: stars: binaries: symbiotics -- stars: individual: Z And

SIMBAD Objects

© ESO 2003