PLATO - Return to the Brightest Stars
The European Space Agency ESA is planning to send a new mission into space in 2026: PLATO, which stands for "Planetary Transits and Oscillations of Stars". On a satellite, 26 telescopes are combined into one instrument to detect exoplanets around bright stars. By combining different methods, astronomers will be able to assess how habitable the new worlds are.
More than 2000 years ago, the Greek astronomer Hipparchus (around 190 - 120 BC) systematically created a star catalog in which he noted their positions and brightnesses. Because he made his observations with the naked eye, this catalog was limited to the brightest stars. With the PLATO mission, astronomers are returning to the brightest stars and want to create a catalog of their planets. Whereas the number of stars in Hipparchus' catalog - around 900 stars - was limited by the visibility with the naked eye, today the task is to record the light from the brightest stars using a combination of the world's largest telescopes. The astronomers want to use this to determine the mass, radius and age of the stars and their planets with a level of accuracy that has not been achieved before. Such a catalog of new solar systems will shape our image of planets in our galactic neighborhood for decades to come.
Ever since ancient times, people have wondered about other worlds. We are now the first generation to know that there are planets around other stars. The first planet around a Sun-like star was found in 1995, and the list of extrasolar planets discovered is growing every week. There are currently 4114 (as of September 23, 2019). But what do these exoplanets look like inside? Are they rocky planets? How did they develop? One suspects that although the discovery of the extrasolar planets has fulfilled long-cherished expectations, it has raised many new questions.
The first discoveries were made with ground-based telescopes. In 2007, the European CoRoT satellite mission began searching from space. Among his discoveries was the first rocky planet that could be identified with certainty. NASA's Kepler mission followed in 2009, giving us hundreds of new planets. However, some of them orbit very distant stars, so that no subsequent observations are possible and therefore no further statements can be made beyond the existence, size and orbital period of the planet.
Out of this experience came the idea for a new European mission: PLATO. The acronym stands for Planetary Transits and Oscillations of Stars. The name is based on the important Greek philosopher Plato, because the name links Plato's famous allegory of the cave with the position in which the exoplanet researchers find themselves: They have indications of distant worlds, but cannot see them directly or even make contact with them. but only indirectly infer the actual object. PLATO was selected in 2014 as an M3 mission under ESA's "Cosmic Vision 2015 – 2025 Program". In 2026, PLATO is scheduled to launch into space, beginning a new chapter in the exploration of planetary systems in our galactic neighborhood…