An article published in the journal “The Astrophysical Journal” reports the observation of structures in protoplanetary disks that probably were left by newborn and perhaps still developing planets. A team of researchers led by Feng Long of the University of Beijing used the ALMA radio telescope to examine disks surrounding young stars in the Taurus star formation region discovering that of 32 protoplanetary disks 12 were divided into rings, a situation associated with planetary formation.
Just over 450 light years away from Earth, the Taurus star formation region consists of a molecular cloud in which a significant amount of stars formed recently and is still forming. From an astronomical point of view, this region is nearby so it was already the subject of many studies over time and powerful and sensitive instruments such as the ALMA radio telescope (Atacama Large Millimeter/submillimeter Array), inaugurated in March 2013, allowed steps forward in understanding the processes underway in the protoplanetary disks surrounding young stars.
An article published in the journal “Nature Astronomy” in June 2018 reported interesting discoveries on the processes underway in the TMC1A system, within the Taurus molecular cloud, thanks to the ALMA radio telescope. The team that carried out this research was led by Daniel Harsono of the Dutch University of Leiden, who is part of the team that used ALMA again to study in detail 32 protoplanetary disks in that area within the GENESIS-SKA (GEneral conNditions in Early planetary Systems for the life of SKA) project to study planetary formation and prebiotic chemical complexity in preparation for the activation of SKA, the next generation radio telescope.
The researchers found that 12 protoplanetary disks of 32 contain ring structures associated with planetary formation. Such a specific typer of study is still quite new and was previously focused in particular on the brightest young stars because they were the easiest to observe. The consequence is that it was difficult to make a statistic concerning the still uniform disks and the ones showing signs of planetary formation while this new study offers significant numbers because the researchers chose the disks regardless of their stars characteristics.
The image (courtesy Feng Long et al., All rights reserved) shows the 12 protoplanetary disks studied in this research showing a ring structure. The width indication is of 50 au, which means 50 times the average distance between the Earth and the Sun, to give an idea of the scale of the protoplanetary disks shown. The analysis of the characteristics of the rings and their gaps allowed the researchers to rule out the possibility that they were created by other types of processes and to estimate the type of planets that are still forming in those systems. Most are gas planets similar to Neptune and super-Earths except from two of them where the planets appear to be more massive, similar to Jupiter.
The next step of the study of protoplanetary disks will consist of observations that will be carried out with a configuration of the ALMA radio telescope’s antennas in which they’re farther apart. This will improve the resolution and make the antennas sensitive to other frequencies with the possibility to detect other types of dust present in those disks. Feng Long stated that with those adjustments she and her collaborators hope to better understand the origins of the rings and their gaps.
Years of experience in using extraordinary instruments such as the ALMA radiotelescope are allowing to examine more and more star systems in the early stages of their lives, obtaining increasingly detailed information about the processes taking place within them. The Taurus molecular cloud is a fantastic space laboratory in which the remarkable star formation is also offering many examples of planetary formation to discover all its secrets.
