The birth of the biggest stars in the cosmos is still shrouded in mystery, mostly because during their formation they are literally shrouded in dense gas clouds.
To overcome this technical difficulty, researchers at the Universities of Tübingen and Vienna have developed a sophisticated simulation that allowed them to work out what’s happening inside these gas clouds. The research was published in the Monthly Notices of the Royal Astronomical Society.
The researchers saw that after the cloud of gas and dust collapses under its own weight, forming a hot young star, it creates an accretion disk around the central object. The disk slowly rotates, carrying material towards the star.
The disk is gravitationally unstable, so the flow of material towards the center is not smooth but happens in clumps, and every time a clump hits the protostar, there’s a sudden burst of luminosity equivalent to the light of 100,000 Suns. Processes like this had already been known for the first stars in the universe and for small stars like the Sun, suggesting that the formation process for stars is universal.
“It is amazing to see these similarities, as if star formation on all scales and epochs is controlled by a common DNA forged in the early Universe,” said Dominique Meyer, first author of the study and post-doc in the Emmy Noether Group at the University of Tübingen, in a statement.
The reason why we are just learning about how massive stars form in the present-day universe has to do with the fact that by the time they dissipate the gas cloud that spurts them, they are already fully formed.
The simulation also indicates that not all the clumps end up in the central star and some may turn into stars themselves, ending up in a multistellar star system.
“This opaque envelope makes it difficult to directly observe the birth process even with modern telescopes. In other words, we see the cradle in which these stars are born, but we can’t detect the stars themselves,” added Rolf Kuiper, the leader of the Emmy Noether Research Group for Massive Star Formation.
But thanks to this new understanding of the process, we might be able to develop new observational strategies to catch these stellar flares in the act, using telescopes such as ALMA.
