American radio astronomers have discovered a disk around the star HW2 in the constellation Cepheus containing large amounts of ammonia. This luminosity is very young and massive, therefore the research shows how such large objects can actually form.
Ammonia near a newborn star
A study was recently accepted for publication in the journal Astronomy & Astrophysics in which astronomers examined a disk around a massive star that contained ammonia. The scientists were helped by the U.S. National Observatory’s Large Array of Antennas to determine this.
The object of the study was the star HW2, located in the star-forming region Cepheus A at a distance of 2300 light-years from Earth. In such regions, newborn luminaries and gas are in chaotic interaction. Therefore, the researchers were able to isolate the part of the ammonia that is directly related to this star by tracking it with spectrometry.
It turned out that this ammonia forms a huge disk with a diameter of 200 to 700 a. e. around the star HW2, which is many times more massive than the Sun. By comparison, in the solar system, Neptune’s orbit is only 40 a.u. away from the sun.
Role of disks in the formation of massive stars
The scientists were also able to determine that the matter in the disk was simultaneously moving in a circle and falling on the star. After all, it increases the mass of HW2 by two thousandths of a solar mass per year. And that’s actually a lot. This is the largest result for all protoplanetary disks around young stars known to scientists.
This process continues even after HW2 has 16 times the solar mass. And this result is extremely important for science. The fact is that for many years, scientists argue whether massive stars are formed, which will then die in a supernova explosion in the same way as their smaller relatives, which, after passing the stage of a red giant, turn into white dwarfs, or have some of their own mechanism of formation.
A new study suggests that their formation mechanism is the same – accretion disks – and these formations may be more complex than previously thought. The same HW2 has an asymmetric disk, which explains well where the streams of matter that often fly away from young stars come from.
According to phys.org
