The discovery of planets orbiting other stars was one of the greatest breakthroughs in modern astronomy.
For thousands of years, no one knew for sure whether there were any planets beyond our solar system, known as exoplanets. Confirming their existence sent a thrill of excitement through the scientific community and the general public alike. Now, there are over 4,000 confirmed exoplanets and thousands more candidates.
But nature has surprised astronomers with the enormous and unexpected diversity of these other worlds. We still struggle to understand that diversity and how our solar system fits into the menagerie.
Roman will advance our understanding of exoplanets along three complementary fronts. These approaches will provide the most comprehensive view yet of the formation, evolution, and physical properties of planetary systems. Roman’s exoplanet studies will also take us another step closer to discovering another "pale blue dot" — a habitable, Earth-like planet orbiting a nearby star.
Roman's Galactic Bulge Time Domain Survey will provide an unprecedented sample of planets detected by gravitational microlensing, and will be particularly sensitive to planets that are about as far from their star as the Earth is from the Sun. It will also enable exoplanet detection by the transit method, studies of variable star physics, and insights into the structure of our Milky Way Galaxy.
The Coronagraph Instrument will demonstrate a suite of new starlight suppression technologies that have never been flown before on a space mission. In this way, the Roman Coronagraph will serve as a pathfinder for future space telescope missions that aim to directly image habitable, Earth-like exoplanets. If the Coronagraph reaches sufficient performance level, it may take the first ever image of a gas giant exoplanet seen in reflected starlight. The Roman Coronagraph will also image circumstellar debris disks around nearby stars in scattered light, which contain clues to how planets form and evolve.
