Massive Hypervelocity Runaway Stars in the Large Magellanic Cloud

Abstract

Since the hypervelocity stars were discovered in the Milky Way, various mechanisms have been proposed to explain these runaway stars. Up to now, however, the dominant ejected mechanism of hypervelocity stars is still unclear. As the largest and closest face-on satellite galaxy of the Milky Way, the Large Magellanic Cloud (LMC) serves as a good target, allowing us to study this issue. Based on the high-precision astrometric parameters provided by Gaia Data Release 3, we researched the proper motions of 3119 massive O–B2-type stars in the LMC and identified 98 (∼3%) as having the ability to escape from the LMC, with more than 50% confidence. Furthermore, by investigating the characteristics of the identified massive stars and adopting a regression analysis, we find that the dynamic ejection scenario might be the dominant mechanism of the massive hypervelocity runaway stars in the LMC.