Discovery of a Mega‑Earth Exoplanet
Astronomers have identified the exoplanet GJ 523b, which is classified as a mega‑Earth. With a mass of roughly 23 times that of Earth, it ranks among the most massive known rocky planets outside the Solar System.
Despite its large mass, its diameter is only about 2.5 times Earth’s diameter, indicating an exceptionally high density. The planet’s age is estimated at nearly 170 million years, making it relatively young on cosmic timescales.
The discovery was made by a team from the Wisconsin Center for Origins Research (WiCOR), which catalogued GJ 523b as its first exoplanet. Observations relied on space‑based telescopes and ground‑based spectrographs measuring the host star’s radial velocity.
Compared with other known super‑Earths, GJ 523b displays an unusual mass‑to‑size ratio that challenges current models of planetary interiors. Theoretical work suggests a substantial fraction of iron and silicate material may compose its interior.
Researchers intend to study the system with the James Webb Space Telescope to look for spectral signatures of gases such as carbon dioxide or water vapor. Such data could reveal geological activity or even hint at habitability, although the high surface temperature due to close proximity to its star makes this unlikely.