New images of a young star that sits around 450 light-years from Earth revealed it may be the very earliest stages in the formation of planets. Using the Karl G. Jansky Very Large Array (VLA), scientists were able to see in unprecedented detail the inner portion of a dusty disk surrounding the star.
Using the Atacama Large Millimeter/submillimeter Array (ALMA), scientists studied the star and its disk back in 2014. The image it produced at the time was considered to be the best image ever taken of a planet formation in progress.
According to the National Radio Astronomy Observatory (NRAO), the gaps in the disk in the ALMA image are presumed to have been caused by planet-like bodies sweeping out the dust along their orbits. The image shows what theorists have suggested for years. However, what is surprising is the star, called HL Tau, is only around a million years old, and that’s very young by stellar standards.
The ALMA image showed details of the system in the outer portions of the disk, however, in the inner portions of the disk, nearest to the young star, the thicker dust is opaque to the short radio wavelengths received by ALMA, the NRAO added.
Astronomers had to turn to the VLA, which receives longer wavelengths, to study this particular region. The VLA images showed the region in greater detail than any previous studies, revealing a distinct clump of dust in the inner region of the disk. Scientists believe that this clump contains close to 3 – 8 times the mass of the Earth.
Thomas Henning of the Max Planck Institute for Astronomy (MPIA), said in a statement:
“We believe this clump of dust represents the earliest stage in the formation of protoplanets, and this is the first time we’ve seen that stage.”
Carlos Carrasco-Gonzalez from the Institute of Radio Astronomy and Astrophysics (IRyA) of the National Autonomous University of Mexico (UNAM), added:
“This is an important discovery, because we have not yet been able to observe most stages in the process of planet formation.
“This is quite different from the case of star formation, where, in different objects, we have seen stars in different stages of their life cycle. With planets, we haven’t been so fortunate, so getting a look at this very early stage in planet formation is extremely valuable.”
The VLA data indicates that grains as large as 0.39 in (1 cm) in diameter are contained within the inner region of the disk. It is this region that scientists think Earth-like planets would form, with clumps of dust growing by pulling material in from their surroundings. Over time, they would collect enough mass to form solid bodies, which would continue to slowly grow into planets.
Claire Chandler of the National Radio Astronomy Observatory (NRAO), said:
“These VLA observations are the most sensitive and show the most detail of any yet made of HL Tau’s disk at these longer wavelengths.
“The VLA’s ability to produce such high-quality images in this region is very important to advancing our understanding of these initial stages of planet formation.”