OGLE-SMC-LPV-00861 (LIN 9): the first proven Z And outburst in a Magellanic symbiotic star

TL;DR

This paper reports the discovery and analysis of the first proven Z And-type outburst in a Magellanic symbiotic star, OGLE-SMC-LPV-00861, highlighting its outburst behavior, spectral features, and implications for understanding symbiotic star phenomena.

Contribution

It provides the first confirmed Z And outburst in a Magellanic symbiotic star, demonstrating the potential of large surveys to identify such systems and offering new insights into their outburst mechanisms.

Findings

First proven Z And outburst in a Magellanic symbiotic star.

Multiple-maxima outburst behavior over ~1200 days.

Significant increase in hot component luminosity during outburst.

Abstract

We report on the discovery of a new Small Magellanic Cloud (SMC) symbiotic star, OGLE-SMC-LPV-00861, previously catalogued as H$\alpha$ emission line source LIN 9. The OGLE light curve shows multiple-maxima outburst behaviour over $\sim$1200 d with a maximum outburst of $\Delta V=1.5$ mag. An optical spectrum of LIN 9 taken with the Southern African Large Telescope (SALT) at quiescence reveals a K5 red giant with emission lines confirming its symbiotic star nature, demonstrating the potential use of ongoing large time-domain surveys to identify strong symbiotic star candidates. It is the first Magellanic symbiotic star proven to show poorly understood Z And outbursts. At outburst the estimated hot component luminosity is $L\sim3165$ $L_\odot$, compared to $L\sim225$ $L_\odot$ at quiescence. Further observations are needed, especially at outburst, to better understand this unique Z And-like system at a known distance, and to provide essential input to physical models of the Z And phenomenon.