banner credit : NASA/W. Stenzel
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 microlensing survey will monitor 200 million stars toward the center of our galaxy. Astronomers expect the survey to reveal thousands of planets in the habitable zone of their stars and farther out, thanks to the light-bending effects of massive objects.
The telescope will be fitted with “starglasses” – a coronagraph instrument that will block out the glare from stars and reveal planets in orbit around them. The coronagraph will provide the first in-space demonstration of technologies needed for future missions to image and characterize rocky planets in the habitable zones of nearby stars.
Since Roman’s microlensing survey involves tracking the amount of light coming from distant stars over time, astronomers expect it to also reveal as many as 100,000 transiting planets. These worlds dim the light of their host stars when they cross in front of them.