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

We report on the discovery of a new Small Magellanic Cloud symbiotic star, OGLE-SMC-LPV-00861, previously catalogued as Hα emission line source LIN 9. The OGLE light curve shows multiple-maxima outburst behaviour over ∼1200 d with a maximum outburst of ΔV = 1.5 mag. An optical spectrum of LIN 9 taken with the Southern African Large Telescope 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 ∼ 3165 L_⊙, compared to L ∼ 225 L_⊙ 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.