Astronomers have for the first time observed a conveyor belt-like streamer from a dense molecular cloud fueling the growth of a young binary star system, according to a new study.
New stars typically form from dense pockets of gas and dust inside big, fluffy molecular clouds. These pockets are called envelopes.
As they pull in surrounding material, they begin to swirl and flatten, forming a disk. Protostars develop as more and more material flows toward the center of the swirling disk.
Astrophysicists in France and Germany were able to observe this refueling process for the first time, according to a study published this week in the journal Nature Astronomy, which details imaging a streamer connecting the outer regions of an envelop with the inner star-forming disk.
The analysis showed the movement of gas and dust along this conveyor belt is primarily dictated by the gravitational pull of the disk’s center.
Scientists spotted the streamer-supplied protostellar disk inside the Perseus Molecular Cloud, located roughly 1,000 light-years from Earth. The newly discovered protostellar disk is home to two protostars.
Previous investigations of protostellar disks have mostly zoomed-in to focus exclusively on the disk itself, but the new study allowed researchers to investigate the links between protostellar disks and the broader molecular cloud structures.
“Numerical simulations of disk formation usually focus on single protostar systems,” lead study author Jaime Pineda,said in a news release.
“Our observations take the idea one step further, by studying a streamer of chemically fresh material from large distances down to scales where we expect a disk to form around a close pair of young protostars,” said Pineda, a researcher at the German Max Planck Institute for Extraterrestrial Physics.
Scientists were able to track the movement and speed of molecules moving from the outer regions of the envelop to the disk-forming region, a distance spanning approximately 10,500 astronomical units. One astronomical unit is roughly the distance from the Earth to the sun.
The movement patterns observed by researchers match those predicted by models that simulate material free-falling from large to small scales.
“It’s not that often that theory and observations match up so clearly,” said study co-author Dominique Segura-Cox, researcher at MPE. “We were excited to see this confirmation of what the telescope’s images were trying to tell us.”
Scientists estimated that the streamer supplies as much as one third of the total material inside the protostellar disk, which researchers estimate contains material measuring three solar masses.
“The streamer must indeed bring in chemically fresh material from the outer regions on a relatively short timescale,” adds Pineda. “The clear identification of such a large reservoir of fresh material in almost free-fall is remarkable.”
The new research suggests the composition of the outer regions of envelopes and the surrounding regions inside the molecular cloud play important roles in dictating the formation of young star systems.
The observations also suggest streamer dynamics influence the chemical composition of protostellar disks.
“The molecule which allowed us to discover the streamer has three carbon atoms, HCCCN, which will then be available to enrich organic chemistry — on its way toward prebiotic compounds — during the phase of planet assembly,” said study co-author Paola Caselli, director at MPE.