SOUL (ESO/NAOJ/NRAO)
A team of scientists has discovered that the dust rings of newly formed planets could be the key to determining their mass.
Advances in observation technologies, such as Atacama Large Millimeter/submillimeter Array in Chile, allowed researchers to closely observe the protoplanetary disksthe rings of dust and gas that make up a star’s planet-forming region. In these observations, astronomers identified that these disks are composed of distinct ring structures.
In a new one, published last month in The Astrophysical Journalthe team revealed their method for extrapolating the mass of a newly formed planet from measurements of the dust rings surrounding its host star, which prevent direct observation of the planet.
According to , researchers suspected that these rings revealed something about the planets already orbiting within the protoplanetary disk, but had been unable to devise a method for interpreting what they were seeing.
“We have long understood that rings could be created from concentrated dust that accumulates just after the orbit of young planets, but until now we have not been able to associate the characteristics of these rings with the masses of the planets,” said the study’s first author, Amena Faruqi.
The team developed computer simulations to model how different planetary masses would influence the shape of dust rings within the protoplanetary disk. The analysis revealed that the width, the amount of dust and the brightest point they are three essential clues in the rings to characterize the planet that shaped them.
The brightest point of the ring has an important significance, related to the mass of the planet and not affected by external factors such as the size of dust grains or the wavelength of observation. Only through this factor is it possible to identify the mass of a newly formed planet obscured by a dusty disk, even without knowledge of its specific conditions.
As a reference, the team turned to one of the only systems whose planets have been directly observed within its disk, the PDS 70. Using their new technique based on the brightest point of five disks, the researchers arrived at a mass value close to those obtained in other estimates.
The team says their research lays the foundation for future identification of planets inside disks, and could even offer new details about how our own Solar System formed.
Because these rings contain enough dust to initiate planet formation, the absence of any such formation within them will be an important focus of astronomical observations and theories in the future.
