2017 Balzan Prize for The Sun’s Planetary System and Exoplanets
A new era of modern astronomy began in 1995 with the discovery of the first planet in orbit around another star. In 2000, the Balzan Prize was awarded to Michel Mayor for this achievement. Since then, more than 3,000 such extrasolar planets have been discovered. A fundamentally interesting and unexpected observation is the unforeseen diversity of these huge numbers of new worlds, which provides a basis for any theory of the formation and evolution of planetary systems, including our own, and for the existence of life in the Universe. Many of the discoveries were made using the indirect method pioneered by Mayor and his collaborators, where the effects of the orbiting planet on the motion of the star is observed. The majority of discoveries of planets in the last decade, however, have been made through observations of the very small, regular variations in the brightness of the star as the planet passes in front of it.
Michaël Gillon is a highly creative scientist who has made very important contributions to the discovery and characterization of new planets, in particular, of planets in orbit around nearby small stars, and similar to the Earth in size and composition. Using telescopes in outer space as well as innovative small robotic telescopes on Earth to search systematically for planets, he has been able to discover a number of quite remarkable planetary systems. Among these is a system which has now been found to contain at least seven Earth-sized planets orbiting a red-dwarf star forty light years away from the Sun. Three of these planets are estimated to be within the so-called “habitable zone” of the star, the region where liquid water is possible on the planet’s surface. Through challenging spectroscopic observations, Gillon has also been able to obtain exciting information about the surface conditions and atmospheres of some of these extra-solar planets.Through his innovative work, Gillon has made a highly significant contribution to the study of extra-solar planets with fundamental consequences for astronomy as well as to the store of ideas about the possibility of life beyond the Earth.