Study of long-term spectroscopic variability of symbiotic stars based on observations of the ARAS Group
Abstract
The importance of small-telescope observations is demonstrated by investigation of long-term outburst activity of the symbiotic systems AG Dra, Z And and AG Peg based on spectroscopic measurements obtained by amateur astronomers organized in the Astronomical Ring for Amateur Spectroscopy. Preliminary results of our ongoing spectroscopic campaign focused on AG Dra are presented.
The temperature of the white dwarf is studied based on behaviour of the prominent emission lines, which are well detectable even in low-resolution spectra. The activity of AG Dra is compared to that of two other symbiotic systems - Z And and AG Peg, which have shown outbursts recently.
Z And is a prototype of classical symbiotic stars which manifested the outburst at the turn of the years 2017 and 2018. AG Peg is the slowest symbiotic nova with the Z And-type outburst in 2015, 165 years after its nova-like flare-up.