The first high-resolution model simulating an entire gas cloud where stars are formed has been created, allowing researchers to watch the birth of a star.
A team including astrophysicists from Illinois’s Northwestern University developed the most realistic, highest-resolution 3D simulation of star formation to date.
The result of their efforts is a visually beautiful tool that allows viewers to float around a colourful cloud of gas while stars emerge around them.
Called STARFORGE (Star Formation in Gaseous Environments), the computational framework is the first to simulate an entire gas cloud in full colour high-resolution, and up to 100 times more massive than previously possible.
It also is the first simulation to model star formation, evolution and dynamics while also accounting for things like jets, radiation, wind and nearby supernovae activity.
The researchers aim to explore questions on why star formation is slow and inefficient, what determines a star’s mass and why stars tend to form in clusters.
The team behind STARFORGE come from a variety of institutions including Northwestern, University of Texas, Caltech, University of Toronto and Harvard.
They have already used STARFORGE to discover that protostellar jets – high-speed streams of gas – play a vital role in determining a star’s mass.
By calculating a star’s exact mass, researchers can then determine its brightness and internal mechanisms as well as make better predictions about its death.
‘People have been simulating star formation for a couple decades now, but STARFORGE is a quantum leap in technology,’ said Northwestern’s Michael Grudić.
‘Other models have only been able to simulate a tiny patch of the cloud where stars form — not the entire cloud in high resolution. Without seeing the big picture, we miss a lot of factors that might influence the star’s outcome.’
Claude-André Faucher-Giguère, a senior author on the study said the way stars form is a central question to the field of astrophysics.
‘It’s been a very challenging question to explore because of the range of physical processes involved. This new simulation will help us directly address fundamental questions we could not definitively answer before.’
From start to finish, star formation takes tens of millions of years, meaning that when astronomers see it happen in the night sky – they’re only viewing a snapshot in time.
‘Stars also form in clouds of dust, so they are mostly hidden,’ Grudić said.
For astrophysicists to view the full, dynamic process of star formation, they must rely on simulations and STARFORGE gives one of the most detailed views ever created.
To develop STARFORGE, the team incorporated computational code for multiple phenomena in physics, including gas dynamics, magnetic fields, gravity, heating and cooling and stellar feedback processes.
Sometimes taking a full three months to run one simulation, the model requires one of the largest supercomputers in the world, a facility supported by the National Science Foundation and operated by the Texas Advanced Computing Center.
The resulting simulation shows a mass of gas – tens to millions of times the mass of the sun – floating in the galaxy.
As the gas cloud evolves, it forms structures that collapse and break into pieces, which eventually form individual stars.
Once the stars form, they launch jets of gas outward from both poles, piercing through the surrounding cloud, a process that ends when no gas remains.
After the first lengthy simulation finished running, STARFORGE helped the team discover a new crucial insight into the way stars form.
When the researchers ran the simulation without accounting for jets, the stars ended up much too large – 10 times the mass of the sun.
After adding jets to the simulation, the stars’ masses became much more realistic – less than half the mass of the sun.
‘Jets disrupt the inflow of gas toward the star,’ Grudić said, adding that ‘they essentially blow away gas that would have ended up in the star and increased mass.’
‘People have suspected this might be happening, but, by simulating the entire system, we have a robust understanding of how it works.’
Beyond understanding more about stars, Grudić and Faucher-Giguère believe STARFORGE can help us learn more about the universe and even ourselves.
‘Understanding galaxy formation hinges on assumptions about star formation,’ Grudić said.
‘If we can understand star formation, then we can understand galaxy formation. And by understanding galaxy formation, we can understand more about what the universe is made of.
‘Understanding where we come from and how we’re situated in the universe ultimately hinges on understanding the origins of stars.’
‘Knowing the mass of a star tells us its brightness as well as what kinds of nuclear reactions are happening inside it,’ Faucher-Giguère said.
‘With that, we can learn more about the elements that are synthesised in stars, like carbon and oxygen — elements that we are also made of.’
The study has been published in the journal Monthly Notices of the Royal Astronomical Society.