Researchers solve decades-old stellar mystery - Why stars formed in different environments have similar masses?

A team led by researchers from the University of Texas at Austin have determined why stars formed in different environments have similar masses, a mystery that has captivated astrophysicists for decades.

The team including experts from Carnegie Observatories, Northwestern University, Harvard University and the California Institute of Technology discovered that star formation is a self-regulatory process, meaning stars themselves set their own masses.

This breakthrough discovery may enable researchers to better understand star formation within our own home galaxy - Milky Way - and other galaxies.

Theoretically, the mass distribution of stars - or initial mass function (IMF) - should vary dramatically, but it is virtually universal, which has puzzled astronomers for decades.

According to the researchers, stars much bigger than our sun are rare, making up only 1% of newborn stars. And, for every one of these stars, there are up to 10 sun-like stars and 30 dwarf stars. Observations have found that no matter where we look in the Milky Way these ratios (i.e., the IMF) are the same, for both newly formed star clusters and for those that are billions of years old.

We have discovered that star formation is a self-regulating process. Stars that form in wildly different environments have a similar IMF, because stellar feedback, which opposes gravity, also acts differently, pushing stellar masses toward the same mass distribution," Dávid Guszejnov, STARFORGE project lead and postdoctoral fellow at the Department of Astronomy at UT Austin, said in a statement.

STARFORGE, short for Star Formation in Gaseous Environments, is a multi-institution initiative to develop cutting-edge computer simulations of star formation and to use them to tackle some of the biggest questions in star formation.

The research was completed on two of the most powerful supercomputers in the world: Frontera and Stampede2 of UT Austin's Texas Advanced Computing Center. The findings are published in the journal Monthly Notices of the Royal Astronomical Society.