Astronomers Discover First Extragalactic Accretion Disk, Hinting at Universal Star and Planet Formation

A swirling disk of material feeding a young star in a neighboring galaxy offers evidence that stars and planets form in other galaxies as they do in the Milky Way.

In a groundbreaking discovery, astronomers have detected the first-ever extragalactic accretion disk—a swirling disk of material that feeds a young star—in a galaxy located outside the Milky Way. This finding suggests that the process of star and planet formation is not unique to our own galaxy but occurs throughout the universe. The young star, part of the HH 1177 system, is situated in the Large Magellanic Cloud, a neighboring galaxy located 160,000 light-years away. This remarkable observation was made possible by the Atacama Large Millimeter/submillimeter Array (ALMA), a powerful radio telescope consisting of 66 antennas in Northern Chile.

Unveiling the Extragalactic Accretion Disk

The discovery of the extragalactic accretion disk was a momentous occasion for the team of researchers led by Anna McLeod, a scientist from Durham University. McLeod and her colleagues were alerted to the system’s existence when the Multi Unit Spectroscopic Explorer (MUSE) instrument on the Very Large Telescope (VLT) detected a jet emanating from a forming star. This instrument allowed scientists to observe the visible wavelength range and measure the wavelengths of light emitted by the object, providing valuable insights into its composition.

Confirming the Presence of an Accretion Disk

To confirm the presence of an accretion disk in HH 1177, scientists had to analyze the movement of dense gas surrounding the star. By observing the gas’s velocity, they were able to identify the characteristic variation that serves as a “smoking gun” for the presence of an accretion disk. This variation in velocity is known as redshift or blueshift, depending on whether the observed object is moving toward or away from Earth. The team’s findings provide direct evidence of the formation of accretion disks in other galaxies.

Accretion Disks in and outside the Milky Way

Accretion disks, such as the one observed in HH 1177, form when matter falls toward a young star or another accreting object, like a black hole or neutron star. As the material spirals inward, it carries angular momentum, resulting in the formation of a flattened, spinning disk that gradually feeds matter to the central object. The gas closer to the central object moves faster than the gas at the disk’s outskirts, creating the telltale variation in velocity that indicates the presence of an accretion disk.

Shedding Light on Universal Star and Planet Formation

While bright accretion disks have been observed around objects like supermassive black holes in other galaxies, detecting accretion disks around stars within the Milky Way has proven challenging due to the obscuring effects of gas and dust clouds. However, the situation is different in the Large Magellanic Cloud, where the material birthing young stars is less dense. This allowed astronomers to observe the central star of HH 1177 and potentially witness the early stages of planet formation. This discovery provides a unique opportunity to study star formation in a different galaxy and gain insights into the universal processes that shape our universe.

The Future of Astronomical Advancements

The ability to study the formation of stars and planets in distant galaxies marks a significant milestone in astronomical research. As Anna McLeod highlights, rapid technological advancements in astronomical facilities have made it possible to explore the intricacies of star formation across vast distances and in galaxies beyond our own. This groundbreaking discovery opens up new avenues for understanding the universal processes that shape our cosmic neighborhood.


The discovery of the first extragalactic accretion disk in the Large Magellanic Cloud offers compelling evidence that stars and planets form in other galaxies in a manner similar to our own Milky Way. The observation of the HH 1177 system, made possible by the ALMA telescope, provides a unique opportunity to study the early stages of planet formation in a neighboring galaxy. This breakthrough not only expands our understanding of star and planet formation but also emphasizes the universal nature of these processes. As technology continues to advance, astronomers are poised to unravel more mysteries of the cosmos, unlocking the secrets of our vast and diverse universe.






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