Raman-Scattered HeII 1025 Line in The Symbiotic Binary V1016 Cyg As a Diagnostic Tool of The Wind From Its Mira-Type Donor

Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica, Slovakia

Abstract

V1016 Cyg is a symbiotic binary comprising a Mira-type evolved cool giant and a white dwarf (WD). The WD ionizes a part of the surrounding environment consisting mainly of the giant*s wind. We investigated a weak emission feature at 6545 Å – a result of Raman scattering of the HeII 1025 line photons, emitted in the ionized region around the WD, on the neutral hydrogen (H⁰) atoms located around the giant. Using the scattering efficiency, η, and a simplified ionization model of symbiotic stars (SySs), we determined the mass-loss rate, FX1, from the cool giant in V1016 Cyg to 2 − 3 × 10⁻⁶ M_⊙ yr⁻¹.