NASA Finds ‘First Nearby Super-Earth’ That May Support Alien Life

NASA is exploring a new candidate to be the next Earth. Described as a super-Earth, the exoplanet is orbiting its star within the habitable zone 31 light-years away in the constellation Hydra.

The space agency’s Transiting Exoplanet Survey Satellite (TESS) discovered the new planetary system in February but was just revealed recently. It has three worlds orbiting an M-type dwarf star, called GJ 357. 

GJ 357 is just one-third the mass and size of the Sun. NASA said it is 40 percent cooler than the star in our solar system. 

The potentially habitable planet, named GJ 357 d, appears twice the size of Earth. Among the three planets in its system, 357 d is the farthest from its star.

“GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the Sun,” Diana Kossakowski, of the Max Planck Institute for Astronomy in Germany, said in a press release. “If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface.”

The team reported the discovery in the journal Astronomy & Astrophysics.

NASA estimates GJ 357 d orbits its star every 55.7 days. It is located 20 percent of Earth’s distance from the Sun. 

The agency has yet to determine the exact size and composition of the planet. But initial estimates show it has a mass that makes it potentially one to two times Earth’s size.

The two other worlds in the system are GJ 357 b, which is located 11 times closer to its star than Mercury is to our Sun, and GJ 357 c, the middle planet. 

The discovery team used data from TESS and ground-based stations to confirm the presence of the planetary system. They gathered information dated back to 1998 provided by different stations across the world, including the European Southern Observatory in Chile, the W.M. Keck Observatory in Hawaii and the Calar Alto Observatory in Spain.

GJ 357 d This illustration shows one interpretation of what GJ 357 d may be like. NASA's Goddard Space Flight Center/Chris Smith

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