NASA’s planet-hunting mission TESS found its first potentially habitable planet orbiting a star about 100 light-years from Earth.
The planet is part of a multi-planet system around TOI 700, a small, cool M-dwarf star in the Dorado constellation. It’s only about 40% of our sun’s mass and size, with half of the surface temperature.
The planet is known as TOI 700 d, one of three orbiting the star. It’s at just the right distance to support liquid water on the surface in the star’s habitable zone.
TESS initially misclassified the star, which meant the planets appeared larger and hotter than they are. But several amateur astronomers, including high school student Alton Spencer – who works with members of the TESS team identified the error.
“When we corrected the star’s parameters, the sizes of its planets dropped, and we realised the outermost one was about the size of Earth and in the habitable zone.” – Emily Gilbert, a graduate student at the University of Chicago.
The discovery was later confirmed by the Spitzer Space Telescope.
The find is exciting to astronomers because it’s one of a select few potentially habitable planets discovered outside of our solar system that happens to be the size of Earth.