NASA mission has discovered a second Earth-sized, rocky planet within the habitable zone of its star—the range of distances where liquid water could occur on a planet’s surface.

Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), the astronomers found “TOI 700 e” which is one of only a few systems with multiple, small, habitable-zone planets that we know of.

Astronomers previously discovered three planets in this system, called TOI 700 b, c, and d.

Planet d also orbits in the habitable zone, but the scientists needed an additional year of TESS observations to discover TOI 700 e. “That makes the TOI 700 system an exciting prospect for additional follow-up. Planet e is about 10 per cent smaller than planet d, so the system also shows how additional TESS observations help us find smaller and smaller worlds,” said Emily Gilbert, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory in Southern California who led the work.

TOI 700 is a small, cool M dwarf star located around 100 light-years away in the southern constellation Dorado.

In 2020, Gilbert and others announced the discovery of the Earth-size, habitable-zone planet d, which is on a 37-day orbit, along with two other worlds. The innermost planet, TOI 700 b, is about 90 per cent Earth’s size and orbits the star every 10 days. TOI 700 c is over 2.5 times bigger than Earth and completes an orbit every 16 days.

“The planets are probably tidally locked, which means they spin only once per orbit such that one side always faces the star, just as one side of the Moon is always turned toward Earth,” the US space agency said in a statement late on January 10.

Source: IANS