Umbon

Umbon is an astronomical term that refers to a hypothetical exoplanet firstidentified in 2020 by the Transiting Exoplanet Survey Satellite (TESS). It orbits the G-type main‑sequence star Gliese 725, located approximately 12.5 light‑years from Earth in the constellation of Aquarius. The planet has a radius roughly 1.6 times that of Earth and a mass estimated at 4.5 Earth masses, placing it in the category of super‑Earths. Its orbital period is about 43 days, which puts it inside the star’s habitable zone if one assumes a conventional liquid‑water habitability criterion.

Observational data suggest that Umbon possesses a substantial atmosphere rich in carbon dioxide, with possible traces of water vapor detected by infrared spectroscopy. The planet’s equilibrium temperature is roughly 220 Kelvin, although atmospheric greenhouse effects could raise surface temperatures to a range where liquid water might persist. No moons have been detected as of the latest data releases.

The classification of Umbon has ignited discussion among exoplanetary scientists regarding the composition and potential geology of super‑Earths. Some models predict a rocky core overlapped by a thick mantle of silicates, while others allow for significant water layers or even a subsurface ocean. Future observations with the James Webb Space Telescope and planned ground‑based observatories aim to refine measurements of its atmospheric composition and surface conditions.

The name Umbon was assigned during a collaborative naming campaign organized by the International Astronomical Union. It was chosen to reflect the planet’s shadowed position in its host star’s H‑zone and its potential as an environment where, metaphorically, “umbra” or shade might signal Earth‑like conditions under the right circumstances.