A pair instability supernova occurs when the furnace of reactions in the heart of a star are no longer powerful enough to act against its massive gravity. Then the star collapses spectacularly, as seen here in an image of supernova remnant E0102-72.
Credit: NASA/Chandra
SYDNEY: The universe's first stars blew small galaxies apart when they exploded, effectively quashing all nearby star formation, say Japanese astrophysicists.
The theory, based on analytical calculations of the energy and disruptive effects of early supernovae, adds another piece to the puzzle of what the first stars were like and how they influenced galaxy formation.
The first stars formed around 200 million years after the Big Bang in clumps of dark matter called dark matter haloes – the basic building blocks of galaxies.
Running out of gas
These stars were massive, probably 10 to 100 times bigger than the Sun. Like most massive stars, they would have burnt through their fuel within a few tens of millions of years and then exploded as either a type II supernova or a pair instability supernova.
The study, published in the current issue of the Astrophysical Journal, looks at what happened to the dark haloes near these massive explosions. Previously, experts were divided as to whether the first supernovae kick started star formation in the haloes or suppressed it.
Astrophysicists Masaru Sakuma from the University of Tsukuba, in Tsukuba, and Hajime Susa from Konan University in Kobe, Japan, say their model shows the shockwave from these supernovae would have expanded the gas shell within the stars' own galaxies, creating a gaseous 'wind' that stripped the gas out of nearby dark haloes.
First clues
This 'wind' would have swept the gas from dark haloes within a radius of up to 5,000 light-years around the supernova, depending on the force of the initial explosion and the mass of the dark haloes, the researchers say.
"[If] a neighbouring halo is located very close to the centre of the supernova explosion, the gas in the halo would be evacuated by the shock momentum... supernova feedback has basically negative effects on the star formation in surrounding halos," the researchers write.
Commenting on the research, Australian theoretical astrophysicist Stuart Wyithe, from the University of Melbourne, said the research answered a "little bit" of the big question of how the death of the first stars affected the early universe.
