Disc vital to forming stars and planets found outside Milky Way in astronomical first
Astronomers exploring a neighbouring galaxy have found evidence of a disc like those which help form stars and planets in our own Milky Way.
It was discovered in the Large Magellanic Cloud, surrounding a massive young star which is still growing in size.
It’s the first time a disc of its type has ever been identified outside our galaxy.
Professor Anna McLeod, from Durham University, said she “could not believe” the data she was seeing when it was detected by a telescope called the Atacama Large Millimeter Array (ALMA).
“It was a special moment,” she said.
“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.”
These rotating discs surrounding young stars are made up of gas and dust.
Known as accretion discs, they feed the growth of stars and planets as the material clumps together, pulled in by gravity and electrical charge.
Huge stars such as the one at the centre of this disc form much more quickly than low-mass stars like the sun, but also live far shorter lives.
This one is estimated to be around 15 times the mass of the sun.
Immense power of modern telescopes – with more to come
The findings, detailed in the journal Nature, follow previous observations by the Very Large Telescope (VLT).
It spotted a jet from a forming star deep inside a gas cloud in the same galaxy, which astronomers suspected was a sign that a spinning disc was present.
Accretion disks very often have astrophysical jets coming from the object in their centre.
To confirm, the astronomers set about measuring the movement of the dense gas around the star – which is where the powerful ALMA telescope in northern Chile came in.
It’s given astronomers a clearer picture of how planets form outside our galaxy, despite the Large Magellanic Cloud – which is one of the nearest neighbours to our galaxy – being some 160,000 light years away.
The VLT, which is operated by the European Space Observatory (ESO), also in northern Chile, previously uncovered the remains of the first stars in the universe dating back 13.5 billion years.
It’s also provided insight into the formation of planets like Jupiter.
Astronomers will have even more power to draw on when the ESO’s Extremely Large Telescope is built.
It’s under construction in Chile’s Atacama Desert and could be finished by 2028.
Prof McLeod said: “We are in an era of rapid technological advancement when it comes to astronomical facilities.
“Being able to study how stars form at such incredible distances and in a different galaxy is very exciting.”