Science and Technology News

Mega Earth GJ 523b

August 24 , 2026 12 hrs 0 min 10 0

Scientists have identified GJ 523b, an exoplanet classified as a “mega-Earth”.
It has a radius about 2.55 times Earth’s, a mass of 23.5 Earth masses, and a density of about 7.8 g/cm³.
It orbits a mid-K dwarf star once every 17.75 days, with an estimated equilibrium temperature of 538 K.
Its properties were determined using transit observations from NASA’s Transiting Exoplanet Survey Satellite (TESS) and radial velocity measurements from the NEID spectrograph on the WIYN 3.5-metre Telescope.
A “mega-Earth” is a rocky exoplanet with a radius of at least 2.1 Earth radii and density of at least 5.5 g/cm³.
The planetary system is estimated to be 169 million years old; its unusually massive rocky nature challenges expectations that such a planet would develop a thick gas envelope.