Trappist-1 Exoplanets

We have discovered so far more than 5,000 exoplanets orbiting other stars. Trappist-1a is a red dwarf star 1/8th the Sun’s diameter. It’s cooler (4,000°F) and older (7.6 billion years) than the Sun, and it’s orbited by seven planets ranging in size from just smaller than to just larger than Earth. They all orbit much closer to Trappist-1a than Earth does from the Sun. Our line of sight to this system is in the plane of the planets’ orbits. These planets were discovered when they transited in front of the star, slightly diminishing its brightness. In this simulation, they appear as black dots while passing in front of the star. When planets pass behind the star, before being eclipsed, they appear red because they are illuminated by a red star. Depending on their atmospheres, several of these planets, could have temperatures placing them in the habitable zone, where they could have liquid water on their surface. But X-ray and UV radiation from giant flares on Trappist-1a may make them uninhabitable.