Washington: NASA's new exoplanet hunter Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size world. The planet, HD 21749c, is about 89 per cent of Earth's diameter, NASA said on Tuesday.

The planet orbits HD 21749, a K-type star with about 70 per cent of the Sun's mass located 53 light years away in the southern constellation Reticulum, and is the second planet TESS has identified in the system.