An article published in the journal “Nature Astronomy” reports the observation of natural masers that revealed a heat wave in the protostar G358.93-0.03-MM1, or simply G358-MM1. A team of researchers led by Ross Burns of NAOJ (National Astronomical Observatory of Japan) carried out the detections as part of the M2O (Maser Monitoring Organization) network of astronomers, specialized in the study of astrophysical masers to understand their nature. In the specific case, it’s a massive protostar and the heat wave coming from it confirms that this type of star passes through a non-linear formation process.
Supernovae observations are providing a lot of information on the agony and death of massive stars, but information on the processes leading to their birth is still only partially known. Research indicates that the birth of medium-small stars such as the Sun and smaller ones is linear and therefore easier to describe in theoretical models.
The main problem in massive star formation models is due to the enormous gravitational pressure that exists inside a protostar that is already much more massive than the Sun because it triggers nuclear fusion when the growth process is still in progress. The energy produced by nuclear fusion generates a force opposite to gravitaty which makes that growth process more complicated. To overcome that resistance, growth could take place in bursts with large amounts of matter that are absorbed in a short time causing a temporary strong increase in brightness. These are brightness fluctuations that are difficult to observe because the protostar is still surrounded by a significant amount of gas and dust.
The image (NASA/JPL-Caltech/R. Hurt (SSC)) shows an artist’s concept of a protostar that grows thanks to the gas it absorbs from the disk. All around it there’s a large cloud of gas and dust which makes it difficult to observe the processes taking place during that growth.
The detection of natural masers, emissions due to thermal phenomena that occur around the star at frequencies that pass through the dust, is of great help in the study of massive protostar such as G358-MM1. They occur in very short time from an astronomical point of view, which means in a time in the order of weeks. In this case the LBA radio telescope detected those maser emissions in details never seen before.
The coordination within the M2O network allows to share information on events such as sudden maser emissions from the protostar G358-MM1 in a very short time and therefore to observe them with other radio telescopes. The subsequent coordination of different instruments at different wavelengths offers more complete results. In this case, it offered new information on the growth of massive protostars.
