Astronomers have discovered two baby stars in the [BHB2007] 11 system. Through an extremely high-resolution image they have concluded that the young stars are being fed by a complex pretzel-shaped network of filaments of gas and dust.
The remarkable find sheds new light on the earliest phases of the lives of stars.
Feeding on circumstellar disks
"We see two compact sources that we interpret as circumstellar disks around the two young stars," explained Felipe Alves from the Max Planck Institute for Extraterrestrial Physics (MPE) who led the study.
The circumstellar disk refers to the ring of dust and gas that encircles young stars. Normally, the star accretes matter from the ring to grow in size. "The size of each of these disks is similar to the asteroid belt in our Solar System and the separation between them is 28 times the distance between the Sun and the Earth," noted Alves.
The discovery also shows two circumstellar disks that are surrounded by a bigger disk that displays a complex network of dust structures distributed in spiral shapes that the astronomers have called "the pretzel loops."
"This is a really important result," stressed Paola Caselli, managing director at MPE, head of the Centre of Astrochemical Studies and co-author of the study. "We have finally imaged the complex structure of young binary stars with their feeding filaments connecting them to the disk in which they were born. This provides important constraints for current models of star formation."
It is assumed that the two baby stars accumulate mass from the bigger disk in two stages. In the first stage, mass is given to the disks in twirling loops, which is what the new ALMA image showed. In the second stage, the stars accrete mass from their circumstellar disks.
"We expect this two-level accretion process to drive the dynamics of the binary system during its mass accretion phase," adds Alves. "While the good agreement of these observations with theory is already very promising, we will need to study more young binary systems in detail to better understand how multiple stars form."
This research was presented in a paper published on 3 October 2019 in the journal Science.