Nebular Hypothesis Validated; ALMA Images Shed Light On Formation Of Stars, Planets From Accretion Disks
Innumerous theories on the formation of stars and planets have been proposed. While most of them were rejected due to unavailability of firm evidence, the ones that prevailed are questioned every now and then. Nebular hypothesis is one such theory. According to it, stars and planets are formed from giant clouds of dust and gas. These clouds form accretion disks and feed the star.
The nebular theory faced criticisms from many astrophysicists, especially because no scientists have ever been successful in proving the existence of such disks. All such speculations were laid to rest after a group of scientists from the U.S. and Taiwan captured images of an accretion disk spinning around a 40,000-year-old young star named IRAS 05413-0104, Universe Today reported.
The said images were captured by the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope. It is one of the most advanced telescopes ever made. After years of arduous efforts and expenditures of $1.4 billion, ALMA became functional four years ago. Since then, it has been used by researchers to explore previously obscure realms of space.
An article that was recently published in the Science Advances journal presented the most recent achievement of ALMA. The published images provide clear illustration of an accretion disk. It also shows the ejecting gaseous jets visible at the center of the disk. This helped in negating the previously proposed theory of non-spinning of accretion disks.
According to the scientists who captured the images, the disk resembles a giant hamburger that is rotating in an inward direction. Further analysis of the disk revealed that its radius is around 60 astronomical units (AU). Furthermore, the equatorial region of the disk is slightly darker and is sandwiched between relatively brighter top and bottom surfaces.
Apparently, these accretion disks are made up of iron and silicate matter that condensed to form stars and planets. The exact mechanisms that mediate this process is yet unknown. Experts believe scientific breakthroughs just like this may soon lead to deciphering the hidden cosmic secrets behind the formation of stars and planets, including Earth.