Discovery Alert 📣 A second Earth-sized planet is found lurking in a nearby star’s habitable zone. It joins three other planets in a red dwarf system 100 light-years away in the Southern constellation Dorado.

Newly discovered Earth-size planet TOI 700 e orbits within the habitable zone of its star in this illustration. Its Earth-size sibling, TOI 700 d, can be seen in the distance. Credit: NASA/JPL-Caltech/Robert Hurt

Using data from NASA’s Transiting Exoplanet Survey Satellite, scientists have identified an Earth-size world, called TOI 700 e, orbiting within the habitable zone of its star – the range of distances where liquid water could occur on a planet’s surface. The world is 95% Earth’s size and likely rocky.

Astronomers previously discovered three planets in this system, called TOI 700 b, c, and d. Planet d also orbits in the habitable zone. But scientists needed an additional year of TESS observations to discover TOI 700 e.

“This is one of only a few systems with multiple, small, habitable-zone planets that we know of,” said Emily Gilbert, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory in Southern California who led the work. “That makes the TOI 700 system an exciting prospect for additional follow up. Planet e is about 10% smaller than planet d, so the system also shows how additional TESS observations help us find smaller and smaller worlds.”

Discovery Alert 📣
A second Earth-sized planet is found lurking in a nearby star’s habitable zone. It joins three other planets in a red dwarf system 100 light-years away in the Southern constellation Dorado. https://t.co/82uDGPvgUt pic.twitter.com/oFRy2MQhNo

— NASA Exoplanets (@NASAExoplanets) January 10, 2023