An article submitted to “Astrophysical Journal Letters” describes a research on the forming planets in the HL Tauri system. An international team used the Karl G. Jansky Very Large Array (VLA) radio telescope to observe new details of what appear to be the first stages of the aggregation of dust and various materials around their star.
The use of the VLA to observe the HL Tauri system isn’t random but due to the fact that it’s become a sensation in the astronomy field after being studied using the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope. After the first study carried out in 2014 there was skepticism about the presence of planets in formation because the star looked too young but a second study carried out in 2015 brought new evidence.
ALMA is a fabulous instrument but was built for observations at millimeter and submillimetre wavelengths. This constitutes a problem for this research because in the innermost area of the dust disk around the star HL Tauern the thickest dust is opaque to those radio waves. Here’s the reason why this new research was carried out using the VLA, which can detect radio waves of longer wavelengths, which are not filtered in the same way by the dust.
The result is that the VLA detected radio waves at a wavelength of 7 millimeters. They showed the inner area of the dust disk around HL Tauri with more detail than ALMA. In particular, the VLA showed a clump of dust for a total mass estimated between 3 and 8 Earth masses. Very probably that’s the first stage of existence of a protoplanet, observed for the first time on this occasion.
Analyzing the data gathered with the VLA the researchers concluded that in the protoplanetary disk’s inner region there are grains of dust with a diameter around a centimeter (almost half an inch). In that area rocky planets, like Earth, may form thanks to the progressive growth of the clumps.
Carlos Carrasco-Gonzalez of the Institute of Radio Astronomy and Astrophysics (IRyA) of the National Autonomous University of Mexico (UNAM), the lead author of the article, stressed the importance of this discovery. He noted that astronomers managed to observe stars at various stages of their life but this had never happened with a planet. In essence, it’s a another step forward in our understanding of this type of process.
