Astronomers Discovered A New Type Of Potentially Habitable Exoplanet

Astronomers are using multiple instruments to scan the heavens looking for exoplanets that could support life. Typically, that search involves looking for planets similar in size, temperature, and mass to the Earth. The planets also have to have an atmospheric composition similar to our own.

However, astronomers working on a new study now believe they have identified a new type of habitable planet called "Hycean" planets. This type of planet is covered in a global ocean and has a hydrogen-rich atmosphere. Researchers say Hycean planets are more numerous and observable than planets there like Earth.

The new class of exoplanet could offer astronomers a completely new approach to searching for potentially habitable worlds. So far, there have been multiple Hycean candidates identified by scientists, and all are both larger and warmer than Earth. However, all of these candidate planets do have the characteristics required to host large oceans potentially able to support microbial life.

Hycean exoplanets also survive in a larger habitable zone than Earth-like planets can be found in. That means they might be able to support life despite being outside the Goldilocks zone required for planets similar to Earth to host life. A recent study looked at a mini-Neptune world called K2-18b and found the planet could support life.

The discovery of that planet prompted a thorough investigation into the full range of planetary and stellar properties providing conditions that could enable a planet like K2-18b to form. Scientists found that Hycean worlds could be as much as 2.6 times larger than Earth and atmospheric temperatures of nearly 200 degrees Celsius. Despite those extreme properties, the oceans could still have conditions that would support microbial life. Astronomers did find that multiple trace terrestrial biomarkers they believe are present in Hycean atmospheres could be detected with spectroscopic observations in the near future.