Free Astronomy Magazine March-April 2022

21 MARCH-APRIL 2022 ASTRO PUBLISHING T his video shows a hypothetical journey from Earth to Proxima b, an exoplanet orbiting the closest star to the Sun, Proxima Centauri. Leaving the Solar Sys- tem, one recognizes the Southern Cross (Crux) constellation and the bright stars Alpha and Beta Centauri. Shortly after, we see a faint red star, Proxima Centauri, the weakest component of a triple star system. Eventually, we see Proxima b, the closest exoplanet to Earth. [ESO/L. Calçada/Nick Risinger (skysurvey.org )] dwarfs have in common, including not only the youngest ones, but also those several billions of years old. This is precisely the case for Proxima Centauri, which, at about five billion years old, makes it only a little older than the Sun. If a star’s magnetic activity heavily affects the stability of its light curve and the position of its spectral lines, it goes without saying that that star is not an ideal target in the search for exoplanets, the presence of which is almost systematically in- ferred through minute dips in starlight during transits in front of the stellar disk or through slight os- cillations of the host star’s spectral lines. Nevertheless, discovering one or more planets in orbit around the closest star to the Solar System has been a primary goal for astronomers for decades. This type of research reached its milestone in 2016 when, overcoming all the difficulties posed by the “noise” produced by the flares, a team of astronomers led by Guillem Anglada-Escudé (Instituto de Ciencias del Espacio, Barcelona) discovered the first planet of that star, designated Proxima b. The dis- covery was made by finding a perio- dicity of 11.2 days in the star’s radial