Mass-loss rate by the Mira in the symbiotic binary V1016 Cygni from Raman scattering

Abstract

The mass-loss rate from Mira variables represents a key parameter in our understanding of their evolutionary tracks. We introduce a method for determining the mass-loss rate from the Mira component in D-type symbiotic binaries via the Raman scattering of atomic hydrogen in the wind from the giant. Using our method, we investigated Raman HeII 1025\AA\ --> 6545\AA\ conversion in the spectrum of the symbiotic Mira V1016 Cyg. We determined its efficiency to be 0.102 and 0.148, and the corresponding mass-loss rate 2.0 (+0.1/-0.2) x 1E-6 and 2.7 (+0.2/-0.1) x 1E-6 M(Sun)/year, using our spectra from 2006 April and 2007 July,respectively. Our values of the mass-loss rate that we derived from Raman scattering are comparable with those obtained independently by other methods. Applying the method to other Mira-white dwarf binary systems can provide a necessary constraint in the calculation of asymptotic giant branch evolution.