For the first time ever, astronomers have spotted a young star “giving birth” to another star, reports Phys.org.
The parent — a baby star dubbed MM 1a — weighs 40 times the mass of our sun and is so enormous that, instead of giving birth to planets, it has produced another, tiny star.
This smaller companion — designated MM 1b — is about 80 times smaller than its parent star, weighing less than half the mass of the sun. This star was born from the massive disk of gas and dust surrounding MM 1a — also known as a protoplanetary disk, or the stuff that planets are made of, as previously reported by the Inquisitr.
This peculiar case is described by astronomers as a phenomenon called “fragmented disk” and was detailed in a study published today in the Astrophysical Journal Letters.
“Stars form within large clouds of gas and dust in interstellar space,” said study lead author Dr. John Ilee, a research fellow at the University of Leeds’ School of Physics and Astronomy. “When these clouds collapse under gravity, they begin to rotate faster, forming a disk around them. In low mass stars like our sun, it is in these disks that planets can form.”
“In this case, the star and disk we have observed is so massive that, rather than witnessing a planet forming in the disk, we are seeing another star being born.”
— Phys.org (@physorg_com) December 14, 2018
According to the University of Leeds, the incredible phenomenon was detected with the Atacama Large Millimetre/submillimetre Array (ALMA) in the Atacama Desert of northern Chile. The team’s original focus was to get a highly detailed view of the disk around MM 1a. While scouring the star with help of interferometry — a process that used the combined power of ALMA’s 66 antenna dishes to simulate a 4-kilometer-wide telescope — the scientists stumbled upon MM 1b in the outer region of its parent star’s disk.
Although it’s not unusual for two stars to co-exist in the same system, MM 1a and MM 1b are very different from what astronomers usually see in these situations. In a typical binary system, the two companions often have the same mass, which suggests that they formed at the same time, evolving as siblings.
However, in the case of these two stars, the discrepancy in mass shows that they took shape in different ways. The team speculates that MM 1b was formed in a cold, outer region of its parent star’s disk — which is generally less gravitationally stable and, thereby, prone to fragmentation. This is one of the first examples of a “fragmented disk” to ever be detected around a massive young star.
Another interesting thing about MM 1b — or the star that formed just like a planet — is that it seems to be surrounded by its own disk of gas and dust, which suggests that it could start churning out planets at some point in the future. Nevertheless, if this does happen, the newborn star and its potential planets will have very short lives, Dr. Ilee points out.
“Stars as massive as MM 1a only live for around a million years before exploding as powerful supernovae, so while MM 1b may have the potential to form its own planetary system in the future, it won’t be around for long.”
Going forward, his team plans to survey the two stars in even greater detail next year by extending ALMA’s capabilities to the simulated power of a 16-kilometer-wide telescope.