This animation shows HD 21749 c, an exoplanet about 89% Earth’s diameter. It orbits HD 21749, a K-type star with about 70% of the Sun’s mass located 53 light-years away in the southern constellation Reticulum. A second, bluish exoplanet in the same system, HD 21749 b, appears briefly in the background.
Credit: NASA/JPL-Caltech/R. Hurt (IPAC)
NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size world, named HD 21749 c. It’s about 89% of Earth’s size and orbits HD 21749, a K-type star with about 70% 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. The new world is likely rocky and circles very close to its star, completing one orbit in just under eight days. The planet’s surface is likely very hot, with temperatures perhaps as high as 800 F (427 C). HD 21749 c's host star is bright and relatively nearby, and is therefore well suited to more detailed follow-up studies, which could provide critical information about the planet’s properties.