Historical light-curve and the 2016 outburst of the symbiotic star StHa 169

TL;DR

This study presents a detailed analysis of the light-curve history and recent outbursts of the symbiotic star StHa 169, revealing multiple outbursts over a century and significant spectral changes during the 2016 event.

Contribution

It reconstructs the historical light-curve of StHa 169 from 1897-1951 and documents the spectral and photometric behavior during recent outbursts, providing new insights into its variability.

Findings

Two outbursts in 2009 and 2016 with peak B=13.6

Historical outbursts in 1934 and 1935 with peak B=13.7

Spectral line fluxes increased significantly during 2016 outburst

Abstract

Accurate BVRI optical photometry of StHa 169 has been collected during the period 2005-2016. It reveals two outbursts, in 2009 and 2016, both peaking at B=13.6. The mean brightness in quiescence was B=15.29. In response to the 2016 outburst, the integrated absolute flux of the emission lines increased by a factor of 7 for Balmer, 9 for HeI lines, and 4.5 for HeII 4686, the Balmer continuum turned into strong emission, and [NeV] 3526 and OVI Raman 6825 Ang emissions disappeared. We have reconstructed the 1897-1951 B-band lightcurve of StHa 169 from Harvard historical plates. On top of a slow decline from a large outburst, ending in 1916, several brightenings are visible. Two fast-evolving outbursts, separated by 510 days, occurred in 1934 and 1935, peaking at B=13.7. The brightness in quiescence was the same as we measured in 2005-2016