A nascent star at least eight times larger than the Sun with a detail never seen before : a disk of gas and dust with four spiral arms that rotate around an embryonic star (protostar), fueling its growth .
The sensational discovery was published in the journal Nature Astronomy and is due to international research whose first author is Ross Burns, of the National Observatory of Japan and the Korean Institute of Astronomy and Science. The study also considered the data collected by the Sardinia Radio Telescope (Srt) and the 32-metre single dish radio telescope of the Medicina radio astronomy station (Bologna) .
«Data from radio telescope observations around the world contributed to this discovery – notes Burns -. This data was carefully processed in data centers on three different continents. These activities alone involve the effort of more than 150 people».
Despite their importance in the universe, massive stars are still mysterious and have only recently been discovered to form at the center of rotating disks of gas and dust, called protostellar disks, which have a radius about a thousand times the mean distance which separates the Earth from the Sun (i.e. one thousand astronomical units). Being able to observe the accretion disks of large-mass protostars is a real challenge for astronomers, also because stars like these form inside dense clouds of gas and dust, so much so that they are invisible to currently available optical telescopes.
Observing the large newborn star, called G358-MM1, was possible using the technique called "heat wave mapping" , which exploits the radiation flash generated by accretion.
A total of 24 radio telescopes were used in the research, in Oceania, Asia, Europe and America. All data were combined to produce an image of G358-MM1's spiral disk, with the four spiral arms enveloping the protostar . The spiral arms help carry material from the disk to the center of the system where it can reach the protostar and feed it, according to the new theory, called episodic accretion.
(Unioneonline/D)