Photometric and spectroscopic observations of the outburst of the symbiotic star AG Draconis between March and June 2016

TL;DR

This paper reports on photometric and spectroscopic observations of the 2016 outburst of the symbiotic star AG Draconis, analyzing its brightness, color changes, and temperature variations during the event.

Contribution

It provides detailed observational data and analysis of the outburst, including temperature evolution derived from emission line fluxes, which is novel for this star's 2016 event.

Findings

Double-peaked outburst with 0.6 magnitude increase

Linear variation of B-V color index with V magnitude

Temperature changes inferred from emission line fluxes

Abstract

The symbiotic star AG Dra experienced a double-peaked outburst of 0.6 magnitudes in April and May 2016. Photometry and spectroscopy through the outburst showed the B-V colour index varying linearly with the V magnitude and enabled the temperature variation of the hot star to be calculated from the changing flux in the H beta and He II 4686A emission lines.