15 Sagittarii is a blue-hued binary star system in the southern zodiac constellation of Sagittarius. The estimated distance based upon photometry is around 1300order=flipNaNorder=flip. It is faintly visible to the naked eye with an apparent visual magnitude of 5.37. The system is moving closer to the Sun with a heliocentric radial velocity of around −6 km/s.
Chini et al. (2012) identify this as a double-lined spectroscopic binary star system. It shows a stellar classification of O9.7 Iab, matching a massive O-type supergiant star. Along with the O-type star 16 Sgr (HD 167263), it is ionizing an H II region along the western edge of the molecular cloud L291.
The Washington Double Star Catalog lists four companions within a 2 arcsecond angular radius.