Free Astronomy Magazine January-February 2022

23 JANUARY-FEBRUARY 2022 ASTRO PUBLISHING C omparison of the expected and observed con- traction time for the planets in the V1298 Tau system. [Gabriel Pérez Díaz, SMM] are published in the journal Nature As- tronomy . The study, led by the IAC re- searcher Alejandro Suárez Mascareño, reports the measure- ment of the masses of two giant planets that orbit the young solar-type star V1298 Tau. They were dis- covered in 2019 by a team lead by Trevor David (JPL) using data from NASA’s Kepler space tele- scope, which allowed the measure- ment of their sizes, slightly smaller than Jupiter, and of their orbital pe- riods, 24 and 40 days for V1298 Tau b and e, respectively. “The characterization of very young planets is extraordinarily difficult,” says Alejandro Suárez Mascareño, first author of the publication. The parent stars have very high levels of activity and until very recently it was unthinkable to even try. And he adds: “Only thanks to the combina- tion of detections made with space telescopes, combined with intense radial velocity campaigns from Earth-based observatories and the use of the most advanced analysis techniques, it was possible to begin to see what is happening in such early stages of the evolution of plan- etary systems.“ In fact, for the new measurements of the planetary masses, it was necessary to separate the signals generated by these plan- ets from the signal generated by the star’s activity, almost ten times larger. The study shows that the masses and radii of the planets V1298 Tau b and Nicolas Lodieu, a researcher at the IAC and also a co-author of the work. The results of this work thus help to build a more solid idea of the early evolution of planetary sys- tems like ours. To achieve the measurement of these masses, the study has required a significant observational effort and the collaboration of multiple observatories and institutions from different countries. It has been nec- essary to combine radial velocity measurements from various instru- ments such as the high-resolution HARPS-N ultrastable spectrograph, installed at the Roque de los Mucha- chos Observatory’s Telescopio Nazio- nale Galileo (TNG); the CARMENES high resolution spectrograph, in- stalled at the Calar Alto observatory; the HERMES spectrograph, installed on the Mercator telescope, also at the ORM; and the SES spectrograph, installed in the STELLA telescope at the Teide Observatory. Observations taken from the Las Cumbres Obser- vatory, a network of telescopes lo- cated around the world, have been used to continuously monitor the variations of the star’s activity. c are surprisingly similar to those of the giant planets of the Solar System or in other old extra-solar systems. These measurements, which are the first to be obtained of such young giant planets, allow us to test cur- rent ideas about the formation of planetary systems. “For many years, theoretical models have indicated that giant planets begin their evolu- tion as bodies with a larger size, and later they contract over hundreds millions or even billions of years,” explains Víctor J. Sánchez Béjar, re- searcher at the IAC and co-author of the work. “We now know that they can actually reach a size similar to that of the planets in the Solar Sys- tem in a very short time,” he notes. The study of young systems gives re- searchers clues about what hap- pened during the infancy of our solar system. “We still do not know if V1298 Tau is a normal case and its evolution is similar to that of most planets or if we are facing an excep- tional case; if this were the normal scenario, it would mean that the evolution of planets like Jupiter and Saturn could have been very differ- ent from what we think,“ comments !