Artists conceptual image of the protostar discovered in the severe outer Galaxy. Credit: Niigata University
For the very first time, astronomers have detected a newborn star and the surrounding cocoon of intricate natural molecules at the edge of our Galaxy, which is referred to as the severe outer Galaxy. The discovery, which exposed the hidden chemical complexity of our Universe, appears in a paper in The Astrophysical Journal.
The scientists from Niigata University (Japan), Academia Sinica Institute of Astronomy and Astrophysics (Taiwan), and the National Astronomical Observatory of Japan, utilized the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to observe a newborn star (protostar) in the WB89-789 area, situated in the severe external Galaxy. A range of carbon-, oxygen-, nitrogen-, sulfur-, and silicon-bearing molecules, consisting of complex organic particles consisting of as much as nine atoms, were identified. Such a protostar, in addition to the associated cocoon of chemically-rich molecular gas, were for the very first time detected at the edge of our Galaxy.
The ALMA observations reveal that numerous type of intricate organic molecules, such as methanol (CH3OH), ethanol (C2H5OH), methyl formate (HCOOCH3), dimethyl ether (CH3OCH3), formamide (NH2CHO), propanenitrile (C2H5CN), and so on, are present even in the primordial environment of the severe external Galaxy. Such complex organic molecules potentially serve as the feedstock for larger prebiotic particles.
Top: Radio spectrum of a protostar in the severe outer Galaxy found with ALMA. Credit: ALMA (ESO/NAOJ/NRAO), T. Shimonishi (Niigata University).
Surprisingly, the relative abundances of complex natural molecules in this freshly found item look like remarkably well what is discovered in similar things in the inner Galaxy. The observations suggest that intricate natural particles are formed with comparable efficiency even at the edge of our Galaxy, where the environment is really various from the solar area.
It is believed that the external part of our Galaxy still harbors a prehistoric environment that existed in the early date of galaxy formation. The environmental qualities of the severe outer Galaxy, e.g., low abundance of heavy components, little or no perturbation from Galactic spiral arms, are extremely various from those seen in the present-day solar community. Because of its special attributes, the severe outer Galaxy is an outstanding lab to study star formation and the interstellar medium in the past Galactic environment.
” With ALMA we were able to see a forming star and the surrounding molecular cocoon at the edge of our Galaxy,” states Takashi Shimonishi, an astronomer at Niigata University, Japan, and the papers lead author. “To our surprise, a range of plentiful complex organic particles exists in the prehistoric environment of the extreme outer Galaxy. The interstellar conditions to form the chemical complexity might have continued given that the early history of deep space,” Shimonishi includes.
” These observations have actually revealed that complicated natural particles can be effectively formed even in low-metallicity environments like the outermost regions of our Galaxy. This finding offers a crucial piece of the puzzle to understand how complex organic particles are formed in deep space,” states Kenji Furuya, an astronomer at the National Astronomical Observatory of Japan, and the papers co-author.
It is not yet clear, nevertheless, if such a chemical intricacy is typical in the outer part of the Galaxy. Complex organic particles are of special interest, due to the fact that a few of them are linked to prebiotic molecules formed in area. The group is planning to observe a larger variety of star-forming regions in the future, and wants to clarify whether chemically-rich systems, as seen in our Solar System, are common through the history of deep space.
Reference: “The Detection of a Hot Molecular Core in the Extreme Outer Galaxy” by Takashi Shimonishi, Natsuko Izumi, Kenji Furuya and Chikako Yasui, 1 December 2021, The Astrophysical Journal.DOI: 10.3847/ 1538-4357/ ac289b.
This work is supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (19H05067, 21H00037, 21H01145).
The scientists from Niigata University (Japan), Academia Sinica Institute of Astronomy and Astrophysics (Taiwan), and the National Astronomical Observatory of Japan, utilized the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to observe a newborn star (protostar) in the WB89-789 area, situated in the extreme external Galaxy. Top: Radio spectrum of a protostar in the extreme external Galaxy found with ALMA. It is thought that the external part of our Galaxy still harbors a prehistoric environment that existed in the early date of galaxy formation. Due to the fact that of its unique characteristics, the severe outer Galaxy is an exceptional laboratory to study star formation and the interstellar medium in the past Galactic environment.
“To our surprise, a range of plentiful complex natural particles exists in the primitive environment of the extreme external Galaxy.