Scientists have discovered a massive cloud of molecular gas and dust that is collapsing in on itself giving birth to a collection of giant stars.
A report in the Monthly Notices of the Royal Astronomical Society claims the discovery could help solve one of astronomy's enduring mysteries: How do really massive stars form?
Dr Stuart Ryder of the Anglo-Australian Observatory, one of the astronomers involved in the study, says when it comes to average sized stars, like our Sun, scientists have a good idea of how they form.
But he admits astronomers are still largely in the dark about the processes that create big stars with masses ten or more times that of the Sun.
Hard to study
Massive stars are rare, making up only a few per cent of all stars and scientists think they only form in significant numbers when really huge molecular clouds collapse.
Ryder says "this collapse creates hundreds of stars of different masses, some of which will be really big".
"These big molecular clouds are rare and smaller gas clouds aren't likely to make big stars.
"Those we do know about are usually well over 1000 light-years away, making them hard to study."
Using the CSIRO's 22-metre Mopra radio telescope near Coonabarabran in western New South Wales, scientists discovered a massive cloud of mostly hydrogen gas and dust, three or more light-years across. The cloud is collapsing in on itself and will probably form a huge cluster of stars.
Ryder says the discovery was made during a survey of more than 200 molecular gas clouds.
"This particular gas cloud, called BYF73, is about 8000 light years away, in the constellation of Carina - the keel - in the southern sky."
Evidence for infalling gas came from the radio telescope's spectral readings of hydrocarbons and complex molecules in the cloud. These indicate the gas has a velocity and temperature pattern consistent with collapse.
Ryder says the rate at which the gas is collapsing is spectacular.
"Something like a rate of about 3% of the Sun's mass every year - one of the highest rates known."
The radio telescope observations were confirmed by the Atacama Sub-millimeter Telescope in Chile.
Follow-up infrared observations made with the 3.9-metre Anglo-Australian Telescope showed signs of massive young stars that have already formed right at the centre of the gas clump, and more new stars forming.
Ryder says, "star formation in the cloud was also evident in archival infrared data from both the Spitzer Space Telescope and the Midcourse Space Experiment or MSX spacecraft".
He says the cloud will help astronomers refine their theories on star formation.
"With clouds like this we can test theories of massive star cluster formation in great detail."