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For the first time, astronomers have glimpsed a young star outside the Milky Way surrounded by a dense disk in which planets could form.
The massive star, called HH 1177, and its rotating disk were spotted in the Large Magellanic Cloud, a nearby dwarf galaxy about 160,000 light-years away. This unprecedented discovery could help scientists gain a better understanding of the formation of stars and planets.
The newborn star grows in size by pulling matter from its surroundings. Gas and dust accumulate in a flat disk around the star, known as the accretion disk, as a result of strong gravitational forces. The rotating disk transports the material to the star, which… It becomes increasingly larger. As the mass of a star increases, its gravitational field becomes stronger, thus pulling more gas and dust into the disk.
A massive star like HH 1177 lives fast and dies young, forming even faster, and its age is only a fraction of the age of a star like our Sun. This shortened timeline makes it difficult to observe the early stages of a massive star in our galaxy, as the star and its disk are hidden from view by the dusty material from which it forms.
But the material that makes up stars is contained within the Large Magellanic Cloud Different from the Milky Way Galaxy.
HH 1177 lies within a stellar nursery called N180, which has less dust and less metal abundance. The star is not obscured by a cocoon of gas and dust, providing a distant but clear view.
“When I first saw evidence of a rotating structure in the ALMA data, I couldn’t believe we had discovered the first extragalactic accretion disk,” said lead study author Dr. Anna McLeod, associate professor of physics at UCL. “It was a special moment.” “We know that disks are essential for the formation of stars and planets in our galaxy, and here, for the first time, we see direct evidence of this in another galaxy,” Durham University in the United Kingdom said in a statement.
Astronomers discovered the star, whose mass is estimated to be about 15 times the mass of our Sun, using the Atacama Large Millimeter/submillimeter Array of Telescopes in Chile, known as ALMA. The results were published on Wednesday in the journal nature.
The ALMA observations came as a follow-up to a previous discovery made by the European Southern Observatory’s Very Large Telescope. The Multi-Unit Spectroscopic Explorer, or MUSE, instrument on the telescope captured a stream of material emanating from the young star. HH 1177 was found deep in a gas cloud in the galaxy.
“We have detected a jet emanating from this young massive star, and its presence is a sign of ongoing disk accretion,” McLeod said.
To find out if there was a disk around the star, the team needed to measure how fast the dense gas was moving around the star.
When matter is attracted to a young, evolving star, it does not fall straight away On the heavenly being. Instead, the material flattens and orbits around the star, forming a disk-like structure. The disc rotates faster at its center. The difference in speed can help astronomers determine whether a disk has formed around the star.
“The frequency of light changes depending on how fast the gas emitting light moves towards or away from us,” study co-author Dr. Jonathan Henshaw, a research fellow at Liverpool John Morris University in the UK, said in a statement. “This is exactly the same phenomenon that occurs when an ambulance siren changes pitch as it passes you and the sound frequency goes from higher to lower.
ALMA observations were able to make detailed measurements of the disk’s rotation.
Young stars are not the only celestial phenomena that contain accreting disks. Supermassive black holes also have thin, hot disks of matter orbiting around them and feeding off of them.
“We are in an era of rapid technological advancement when it comes to astronomical facilities,” McLeod said. “Being able to study how stars form at these amazing distances and in a different galaxy is very exciting.”
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