An article published in the “Astrophysical Journal Letters” describes a study on the co-evolution of stars and protoplanetary disks based on the class 0 protostar cataloged as IRAS 15398-3359. A team of astronomers from the Department of Physics at the University of Tokyo led by Professor Yoko Oya used the ALMA radio telescope for this research, discovering a dense disk of materials around the protostar that could be a precursor to a planetary system. This discovery could improve our knowledge of the formation of solar systems.
This research began in 2013, when Professor Yoko Oya and her collaborators used the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope, inaugurated in March of that same year, to study the protostar IRAS 15398-3359. It belongs to the class 0 therefore its peak emissions are at submillimetric wavelengths detectable by ALMA, an excellent instrument for those observations even before all its antennas were put into operation.
About 47 light years away from the Earth, the protostar IRAS 15398-3359 is really tiny since the calculations based on the mass of the cloud of gas and dust that surrounds it indicate that its mass is only 0.7% of the Sun’s. Over the next millennia its mass could increase considerably, however at the moment the estimate is that of a planetary mass being about 7 times Jupiter’s. Previous estimates indicated that its mass is about 4% of the Sun’s, so the question remains open.
Whether in the end IRAS 15398-3359 is a star, a brown dwarf or a planet, the most interesting thing is that the analysis of the data collected revealed structures that are interesting but difficult to interpret. Yuki Okoda, a student at the beginning of her Ph.D, collaborated on the research, creating a model that explains the data collected describing them as a dense disk of materials made of gas and dust from the cloud surrounding IRAS 15398-3359. This had never been seen so far around an object so young and seems to be the precursor of a protoplanetary disk.
The system is so young that the structure is still forming and could be swept away by stellar winds or be swallowed by the protostar, further increasing its mass. The IRAS 15398-3359 system seems really young so it’s difficult to predict its evolution. For this reason it represents an intriguing target of study to better understand the first phase of life of what are called young stellar – or protostellar – objects and generically include stars still in formation and of possible star systems.