Context. The wind mass transfer from a giant to its white dwarf companion in symbiotic binaries is not well understood. For example, the efficiency of wind mass transfer of the canonical Bondi-Hoyle accretion mechanism is too low to power the typical luminosities of the accretors. However, recent observations and modelling indicate a considerably more efficient mass transfer in symbiotic binaries. Aims. We determine the velocity profile of the wind from the giant at the near-orbital-plane region of eclipsing S-type symbiotic binaries EG And and SY Mus, and derive the corresponding spherical equivalent of the mass-loss rate. With this approach, we indicate the high mass transfer ratio. Methods. We achieved this aim by modelling the observed column densities taking into account ionization of the wind of the giant, whose velocity profile is derived using the inversion of Abel's integral operator for the hydrogen column density function. Results. Our analysis revealed the spherical equivalent of the mass-loss rate from the giant to be a few times 10 −6 M yr −1 , which is a factor of > ∼ 10 higher than rates determined by methods that do not depend on the line of sight. This discrepancy rules out the usual assumption that the wind is spherically symmetric. As our values were derived from near-orbital-plane column densities, these values can be a result of focusing the wind from the giant towards the orbital plane. Conclusions. Our findings suggests that the wind from giants in S-type symbiotic stars is not spherically symmetric, since it is enhanced at the orbital plane and, thus, is accreted more effectively onto the hot component.

Context. The star V426 Sge (HBHA 1704-05), originally classified as an emission-line object and a semi-regular variable, brightened at the beginning of August 2018, showing signatures of a symbiotic star outburst. Aims. We aim to confirm the nature of V426 Sge as a classical symbiotic star, determine the photometric ephemeris of the light minima, and suggest the path from its 1968 symbiotic nova outburst to the following 2018 Z And-type outburst. Methods. We re-constructed an historical light curve (LC) of V426 Sge from approximately the year 1900, and used original low-(R∼500-1 500; 330-880 nm) and high-resolution (R∼11 000-34 000; 360-760 nm) spectroscopy complemented with Swift-XRT and UVOT, optical U BVR C I C and near-infrared JHKL photometry obtained during the 2018 outburst and the following quiescence. Results. The historical LC reveals no symbiotic-like activity from ∼1900 to 1967. In 1968, V426 Sge experienced a symbiotic nova outburst that ceased around 1990. From approximately 1972, a wave-like orbitally related variation with a period of 493.4 ± 0.7 days developed in the LC. This was interrupted by a Z And-type outburst from the beginning of August 2018 to the middle of February 2019. At the maximum of the 2018 outburst, the burning white dwarf (WD) increased its temperature to > ∼ 2 × 10 5 K, generated a luminosity of ∼ 7 × 10 37 (d/3.3 kpc) 2 erg s −1 and blew a wind at the rate of ∼ 3 × 10 −6 M ⊙ yr −1 . Our spectral energy distribution models from the current quiescent phase reveal that the donor is a normal M4-5 III giant characterised with T eff ∼ 3 400 K, R G ∼ 106 (d/3.3 kpc) R ⊙ and L G ∼ 1350 (d/3.3 kpc) 2 L ⊙ and the accretor is a low-mass ∼0.5 M ⊙ WD. Conclusions. During the transition from the symbiotic nova outburst to the quiescent phase, a pronounced sinusoidal variation along the orbit develops in the LC of most symbiotic novae. The following eventual outburst is of Z And-type, when the accretion by the WD temporarily exceeds the upper limit of the stable burning. At this point the system becomes a classical symbiotic star.

Context. The orbital inclination of the symbiotic prototype Z And has not been established yet. At present, two very different values are considered, i ∼ 44• and i > ∼ 73• . The correct value of i is a key parameter in, for example, modeling the highly-collimated jets of Z And. Aims. To measure the orbital inclination of Z And. Methods. First, we derive the hydrogen column density (n H ), which causes the Rayleigh scattering of the far-UV spectrum at the orbital phase φ = 0.961 ± 0.018. Second, we calculate n H as a function of i and φ for the ionization structure during the quiescent phase. Third, we compare the n H (i, φ) models with the observed value.Results. The most probable shaping of the H i/H ii boundaries and the uncertainties in the orbital phase limit i of Z And to 59• −2• /+3• . Systematic errors given by using different wind velocity laws can increase i up to ∼74• . A high value of i is supported independently by the orbitally related variation in the far-UV continuum and the obscuration of the O i] λ1641 Å emission line around the inferior conjunction of the giant.Conclusions. The derived value of the inclination of the Z And orbital plane allows treating satellite components of Hα and Hβ emission lines as highly-collimated jets.