Discovery of the first S star in NGC 6822

A spectroscopic survey of the red giants located in a 1.5 x 2.5 arcmin patch of NGC 6822 has led to the discovery of an S star, the first to be identified in a system lying beyond the Milky Way's outer halo. Seven M stars and eight carbon stars have also been spectroscopically confirmed. The S star spectrum shows prominent ZrO and LaO features, while TiO, C2, and CN bands are weak or absent. Infrared photometry yields M(bol) = -5.15 mag, a value similar to that of the only known pure S star in the Magellanic Clouds. The results of the spectroscopic survey also confirm the reliability of a new technique for finding very distant C and M stars from intermediate-band filter photometry.