While astronomers continue to uncover new insights about objects within our solar system, they also keep a close eye on bodies beyond it. A prime example is the exoplanet GJ 1214 b, first observed in 2009. Recent studies suggest it may not fit any of the planet categories we currently know.
Rechristened Enaiposha in 2023, this distant world lies just 48 light‑years from Earth—close enough for the James Webb Space Telescope (JWST) to study in detail. In 2024, JWST captured an unexpected atmospheric signal around the nearby star Vega, prompting a reevaluation of Enaiposha’s nature.
Initially classified as a mini‑Neptune or super‑Earth based on its thick atmosphere, an international research team led by Kazumasa Ohno of Japan’s National Astronomical Observatory and Everett Schlawin of the University of Arizona has proposed a different story. Their analysis, published in The Astrophysical Journal Letters, points to a dense carbon‑dioxide atmosphere with minimal hydrogen and a metal‑rich composition.
According to Ohno, the CO₂ signal is subtle and required rigorous statistical validation to confirm its authenticity. By integrating these observations with advanced theoretical models, the team concluded that Enaiposha’s atmosphere is dominated by heavier elements. If follow‑up observations corroborate these findings, Enaiposha could be the first member of a new “super‑Venus” class—planets with Venus‑like atmospheres yet larger in size.
Venus, our solar system’s closest planetary neighbor, boasts a thick CO₂ atmosphere and sulfuric acid clouds that obscure its surface. It sits 0.72 astronomical units (AU) from the Sun. A super‑Venus would share this atmospheric chemistry but would be considerably larger, with a scorching proximity to its host star—Enaiposha orbits its star at just 0.0149 AU.
In contrast, super‑Earths and mini‑Neptunes are defined by size rather than atmospheric composition. A super‑Earth can be up to ten times Earth’s radius but remains less massive than Neptune, while a mini‑Neptune reaches the upper size limit of a super‑Earth. These planets may be gaseous, icy, or water‑rich, and their extreme temperatures can vaporize metallic constituents.
With over 5,800 confirmed exoplanets, the discovery of a super‑Venus would deepen our understanding of planetary formation and the diversity of worlds that can host dense, carbon‑rich atmospheres.
