Scientists have discovered a spectacular burst of stars in our early galaxy, a flurry of formation that resulted in 100,000 supernova explosions.
The discovery was part of a new survey of the Milky Way, which found new details about how the stars that make up our galaxy were born.
And it allowed the researchers to discover evidence of the dramatic event that brought the stars that surround us into being.
The finding changes our understanding of the story of the Milky Way. Its stars were not formed in one continuous process, they say – but instead in a bright flash that lit up the galaxy.
“Our unprecedented survey of a large part of the Galactic centre has given us detailed insights into the formation process of stars in this region of the Milky Way,” says Rainer Schödel from the Institute of Astrophysics of Andalusia in Granada, Spain, who led the observations.
“Contrary to what had been accepted up to now, we found that the formation of stars has not been continuous,” adds Francisco Nogueras-Lara, who led two new studies of the Milky Way central region while at the same institute in Granada.
In the study, researchers found that roughly 80 per cent of the stars in our Milky Way were formed during its earliest years, between about eight and 13.5 billion years ago. After that came about six billions years during which very few stars were born.
But that quiet period was brought to a dramatic close with a crescendo of star formation, roughly a billion years ago, when stars with a mass of up to a few tens of million Suns formed in its centre over the course of just 100 million years.
That area is now relatively quiet, birthing stars at a rate of one or two of our own Suns each year. But the new observations from the European Southern Observatory’s Very Large Telescope (VLT) allowed to look at it and peer into its path, and how it would have looked in its past.
“The conditions in the studied region during this burst of activity must have resembled those in ‘starburst’ galaxies, which form stars at rates of more than 100 solar masses per year,” said Nogueras-Lara, who is now based at the Max Planck Institute for Astronomy in Heidelberg, Germany, in a statement.
“This burst of activity, which must have resulted in the explosion of more than a hundred thousand supernovae, was probably one of the most energetic events in the whole history of the Milky Way.”
This newly understood period was not simply a flurry of births but of deaths, too. The massive stars that are born in a starburst live for less time than lower-mass stars, dying much sooner in spectacular supernova explosions.
The new discoveries were accompanied by a spectacular picture of the Milky Way’s central region, and both relied on new capabilities of the ESO’s most famous telescope. New instruments allowed the researchers to look through the dust and gas that surrounds the region, and pick up new details that had never been seen before.