For the first time, astronomers have observed a disc around a young star in a galaxy outside of ours called Large Magellanic Cloud. This extragalactic neighbor of our home Milky Way galaxy is located almost 200,000 light-years away from Earth and could crash into our home galaxy in about two billion years.
[Related: A ‘bridge of stars’ connects two of our closest galaxies.]
The new observations were made with the Atacama Large Millimeter/submillimeter Array in Chile. A massive young star in the star system HH 1177 is growing and taking in matter from its surroundings. As the matter gathers, a spinning disc called an accretion disc is forming. This is the first time that astronomers have seen an accretion disc in an extragalactic area. The discovery is described in a study published November 29 in the journal Nature.
“When I first saw evidence for a rotating structure in the ALMA data I could not believe that we had detected the first extragalactic accretion disc, it was a special moment,” Anna McLeod, a study co-author and astronomer Durham University in the United Kingdom, said in a statement. “We know discs are vital to forming stars and planets in our galaxy, and here, for the first time, we’re seeing direct evidence for this in another galaxy.”
This new study follows previous observations of star system HH 1177 made with the Multi Unit Spectroscopic Explorer instrument on the European Southern Observatory’s Very Large Telescope. In 2018, the telescope spotted a jet from a forming star located deep inside a gas cloud in the Large Magellanic Cloud.
“We discovered a jet being launched from this young massive star, and its presence is a signpost for ongoing disc accretion,” said McLeod.
To confirm that there was an accretion disc around the star, the authors needed to measure the movement of dense gas around the young star. As matter is pulled towards this expanding star, it can’t fall directly onto it….
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