Rare Type of Black Hole

August 10, 2025

NASA’s Hubble Space Telescope and Chandra X-ray Observatory have jointly uncovered a rare cosmic event: a black hole devouring a star on the outskirts of a distant galaxy. This discovery, centered on an object known as HLX-1 in the elliptical galaxy NGC 6099, offers compelling evidence of an elusive class of black holes known as intermediate-mass black holes (IMBHs)—a missing link in our understanding of black hole evolution.

Located approximately 450 million light-years away in the constellation Hercules, HLX-1 sits about 40,000 light-years from the center of its host galaxy, nestled within a compact star cluster. Unlike supermassive black holes that dominate galactic cores or stellar-mass black holes formed from dying stars, IMBHs are thought to range from a few hundred to a few hundred thousand times the mass of our Sun. They are notoriously difficult to detect because they don’t typically emit strong radiation unless actively feeding.

In this case, astronomers believe HLX-1 was caught in the act of consuming a star—a phenomenon known as a tidal disruption event. As the star ventured too close, it was torn apart by the black hole’s immense gravity, forming a superheated disk of plasma that radiated intense X-rays. Chandra first detected this bright X-ray source in 2009, and by 2012, it had flared to nearly 100 times its original brightness before gradually dimming over the following decade. The X-ray emissions from HLX-1 reached temperatures of around three million degrees, consistent with the violent energy release expected during a tidal disruption. Hubble added further detail by identifying a dense cluster of stars surrounding the black hole, with stellar neighbors packed just a few light-months apart—providing ample fuel for future feeding episodes.

IMBHs like HLX-1 could play a crucial role in the formation of supermassive black holes, potentially growing over billions of years through mergers and accretion. Their presence in galactic halos suggests that galaxies may host satellite black holes that orbit far from the center, occasionally flaring into visibility when they encounter a star. Learn more at NASA.

The video above is intended for educational purposes and does not constitute or imply an endorsement by FutureForAll.org.