Astronomers have identified sodium chloride molecules and heated water vapor in the circumstellar disk of the binary star IRAS 16547-4247, located 9,500 light-years from Earth.
Using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope, an international team of astronomers spotted a pair of baby massive stars surrounded by a gaseous disk containing sodium chloride molecules (the famous table salt) and heated water vapor.
This is the second time that sodium chloride has been detected around young stars, indicating that, although rare in the Universe, the substance can be an important marker for identifying regions where giant stars are born.
“The first example was around Orion KL Source I, but that is such a peculiar source that we were not sure whether salt is suitable to see gas disks around massive stars,” said study leader Kei Tanaka, a researcher at the National Astronomical Observatory of Japan.
“Our results confirmed that salt is actually a good marker.”
According to the researchers, the presence of heated water vapor and sodium chloride is due to the process of destruction of dust particles during the formation of these stars.
This phenomenon is further evidence of the hot and dynamic nature of the discs that surround young massive stars.
The study, published in August in The Astrophysical Journal Letters, gives new insights about how massive stars form. These stars are more than 10 times larger than our Sun.
In general, these stellar nurseries are difficult to observe because they are very far from Earth and also because they are surrounded by massive clouds with complex structures.
However, scientists were able to identify a wide variety of molecules coming from IRAS 16547-4247 through radio emissions.
In addition to the presence of sodium chloride (NaCl) and heated water (H2O), they also detected acetonitrile (CH3CN) in more distant parts of IRAS 16547-4247, which is located 9,500 light-years from us, in the constellation Scorpius.
They are estimated to have 25 times the mass of the Sun, while the cloud around it is 10,000 times more massive than the Sun.
Another peculiarity about the pair is that their discs rotate in opposite directions.
According to experts, this may indicate that they did not form at the same time, as if they were “twins”, but rather separately, in different clouds, and approached later. Future research will clarify this.
The next generation of the Very Large Array will allow astronomers to better track the molecules released when massive stars form and even find out more about the formation of our own Solar System.