HD 93521
HD 93521 is a single, massive star in the northern constellation of Leo Minor. With an apparent visual magnitude of 7.03, it is too faint to be seen with the naked eye. The star is located at a distance of approximately from the Sun based on parallax measurements. It is positioned at a high galactic latitude of +62° and is located about above the Galactic plane. The spectrum of this star matches an O-type main-sequence star with a stellar classification of O9.5V. It is unusual for a star of this class to have formed so far away from the galaxy's star forming regions. Absorption lines in its spectrum indicate a metallicity that is inconsistent with being a population II star, which are typically found in the galaxy halo. Likewise, HD 93521 is unlikely to be a runaway star or a hot subdwarf, either of which could explain its remote location. It may instead be a blue straggler that was formed as a result of a merger. The resulting star likely began as a close binary system of lower mass, longer-lived stars that were ejected from the galactic disk. The merger would then have reset the evolutionary clock, producing a hotter,