Fast-Moving Stars Uncover Supermassive Black Hole in the Large Magellanic Cloud

WASHINGTON (Reuters) – The Large Magellanic Cloud, a dwarf galaxy situated near our Milky Way, is visible to the naked eye as a luminous patch of light from Earth’s southern hemisphere. Named after the Portuguese explorer Ferdinand Magellan, who observed it five centuries ago, this galaxy has long intrigued astronomers. Recent research has now provided a deeper understanding of our galactic neighbor, revealing the presence of a supermassive black hole at its core.

Evidence from Fast-Moving Stars

A groundbreaking study based on the trajectory of nine fast-moving stars observed at the edges of the Milky Way offers compelling evidence for the existence of a supermassive black hole within the Large Magellanic Cloud. While it is widely accepted that most galaxies harbor such black holes, this marks the first substantial evidence of one in the Large Magellanic Cloud.

According to the researchers, the data on the trajectory of these stars suggests they were ejected from the Large Magellanic Cloud following a violent encounter with this black hole. Black holes are incredibly dense objects with gravitational forces so intense that not even light can escape their grasp.

Proximity to Earth

The Large Magellanic Cloud is located approximately 160,000 light-years from Earth, making it one of the closest galaxies to the Milky Way. This discovery identifies it as the nearest supermassive black hole to us, aside from Sagittarius A* (Sgr A*), which resides at the heart of our own galaxy. Sgr A* is about 26,000 light-years away from Earth.

While the Milky Way is significantly more massive than the Large Magellanic Cloud, Sgr A* is also much more massive than the newly identified black hole, which is among the least massive of any known supermassive black holes. For context, Sgr A* has a mass roughly 4 million times that of the sun, whereas the newly discovered black hole has a mass around 600,000 times greater than the sun.

Comparative Masses of Black Holes

In comparison, Sgr A* is dwarfed by some supermassive black holes found in larger galaxies. For instance, a black hole in the galaxy Messier 87 has a mass 6.5 billion times that of the sun. Notably, Sgr A* and the black hole in Messier 87 are the only two black holes that have been imaged by astronomers.

Hypervelocity Stars and Their Origins

The new study focused on a class of stars known as hypervelocity stars. These stars are produced when a binary star system—two stars that are gravitationally bound to each other—approaches a supermassive black hole too closely. The intense gravitational forces tear the binary pair apart, capturing one star into a tight orbit around the black hole while the other is flung outward at extreme velocities, often exceeding thousands of kilometers per second, thus becoming a hypervelocity star.

Jesse Han, a doctoral student in astrophysics at Harvard University and the lead author of the study published in the Astrophysical Journal, explained, “The intense gravitational forces tear the pair apart. One star is captured into a tight orbit around the black hole, while the other is flung outward at extreme velocities.” This research utilized data from the European Space Agency’s Gaia space observatory, which has tracked over a billion stars in our galaxy with unprecedented precision.

Conclusion

Currently, there are 21 known hypervelocity stars in the Milky Way. The identification of a supermassive black hole in the Large Magellanic Cloud not only enhances our understanding of this nearby galaxy but also opens new avenues for research into the dynamics of black holes and their interactions with surrounding stars. As we continue to explore the cosmos, discoveries like this remind us of the vast and mysterious universe we inhabit. For more detailed insights, you can read the original article here.