NASA discovers evaporating planet that could be a 'super-Earth'

After five months in orbit, NASA's TESS exoplanet hunter has discovered a new planet outside our solar system for the first time.SpaceThe planet orbits the yellow dwarf star Pi Mensae in the constellation Son An, also known as HD 39091, about 59.5 light-years from Earth.

The new exoplanet has been named Pi Mensae c. Lead author Chelse Huang from the Massachusetts Institute of Technology (MIT) in the US said it is likely a super-Earth - a term for rocky planets outside the solar system, 2-10 times more massive than our planet and with a thin atmosphere.

Pi Mensae c is 2.14 times the diameter of Earth and 4.82 times more massive. Density analysis suggests the planet is composed mostly of water, with a rocky core and an atmosphere of hydrogen and helium. "This is a really cool find. Pi Mensae c is exactly the type of exoplanet TESS was designed to find," said Natalia Guerrero of MIT, a member of the research team.

Pi Mensae c is so close to its star, just 1/50th the distance between Mercury and the Sun, that scientists believe it is evaporating due to the amount of radiation it receives. That also means the chances of life on the exoplanet's surface are slim.

TESS is NASA's newest exoplanet hunter. Its primary mission is to survey the brightest stars between 30 and 300 light years away in search of new exoplanets. It is expected to find more than 20,000 planets outside our solar system during its two-year mission.