June 24, 2021

Solar and Space Physics UNIToV

Gruppo di Fisica Solare e Spaziale Università di Roma Tor Vergata

When it rains, it pours on Proxima Centauri b

A new publication on The Astrophysical Journal:“Three-dimensional Climate Simulations for the Detectability of Proxima Centauri b” by Daniele Galuzzo, Chiara Cagnazzo, Francesco Berrilli, Federico Fierli, and Luca Giovannelli Published 2021 March 17 • © 2021. The American Astronomical SocietyThe Astrophysical Journal, Volume 909, Number 2, https://doi.org/10.3847/1538-4357/abdeb4

A group of researchers, coordinated by the Solar & Space Physics Team (SSPT) of the Physics Department of the University of Rome Tor Vergata and also composed of researchers from the ISMAR and ISAC institutes of the CNR Tor Vergata Research Area, reconstructed the possible climate of the extrasolar rocky planet Proxima Centauri B orbiting the star Proxima Centauri, a component of the triple star system Alpha Centauri, the closest to our solar system. The result of the research will help scientists both to understand the climate and dynamics of the atmosphere of the exoplanet Proxima B, connected to the possibility that Proxima B hosts life forms, and to facilitate their study through an estimation of the observability of climatic properties with future large telescopes on Earth, such as the Extremely Large Telescope (ELT), or from space such as NASA’s new James Webb Space Telescope (WEBB). The study showed that the hottest point on the planet’s surface, and perhaps the only one where life on the surface is possible, is not exactly at the sub-stellar point, but is located further east of this region. This is probably due to the atmospheric superrotation associated with the rotation speed of Proxima B. So if a biosphere is present on Proxima B, with the possibility of biological photosynthesis, it will be in the region close to the sub-stellar point, a region that always looks to the star, at least if the planet is synchronized as happens between the Earth and the Moon. Unfortunately, for the eventual inhabitants of Proxima B, this region would probably lie beneath a mighty cloud system. However, what has been foreseen must be confirmed (or refuted) by the observations. For this reason, the study not only analyzed the possible climate of Proxima B but also estimated the possible spectral “signature” of the exoplanet’s climatic properties, providing astrophysicists with the tools to determine the possible presence of this “hot” region on its surface. . The study was made possible thanks to the collaboration of two research groups with decades of experience in the field of solar astrophysics and Sun-Earth relations and terrestrial climatology that have combined their skills to study the climate on the extraterrestrial planet closest to Earth. . PhD students of the Astronomy, Astrophysics and Space Science Ph.D. Program between the universities of Rome (Tor Vergata and Sapienza) were part of the research group with the collaboration of the National Institute of Astrophysics (INAF).