ATLANTA (Pajhwok): A second planet has been found in the habitable zone of a star just 100 light-years from our solar system.
Discovered in data from NASA’s Transiting Exoplanet Survey Satellite, the planet orbits a star called TOI 700, a red dwarf star in the constellation Dorado.
TOI 700 becomes one of very few star systems with multiple, small, habitable-zone planets that astronomers know of.
Red dwarf stars are cooler than stars like our Sun, but much more abundant in our Milky Way galaxy. Red dwarfs account for about 70% of all stars.
The new planet is called TOI 700 e and takes 28 days to orbit its star. About 95 percent Earth’s size and likely rocky, it orbits in the habitable zone of the star, as does another planet called TOI 700 d, which orbits every 37 days.
A habitable zone around a star refers to an orbit that’s close enough to be warm enough allow liquid water on the surface. That’s crucial because scientists believe life can only exist when liquid water is present.
“Planet e is about 10 percent smaller than planet d, so the system also shows how additional TESS observations help us find smaller and smaller worlds, which makes the TOI 700 system an exciting prospect for additional follow up,” said Emily Gilbert, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory in California, who led the work and presented the findings at this weeks 241st meeting of the American Astronomical Society in Seattle. The same researchers also found TOI 700 d in 2020.
There are two other planets orbiting in the same star system—TOI 700 b and c—but they orbit too close to the star and are too hot to allow liquid water. TOI 700 b is around 90% Earth’s size and orbits the star every 10 days while TOI 700 c is over 2.5 times bigger than Earth and orbits every 16 days.