One of the TRAPPIST-1 exoplanets might have an ocean, researchers now say

Ever since astronomers announced the discovery of seven exoplanets around the star called TRAPPIST-1, researchers have been diving into the data in an attempt to determine what the planets are like. Early on, the prospects for potentially habitable worlds seemed good, but subsequent models suggested that the star at the heart of the system may have burned off any atmosphere the planets once had.

Now, a new study claims to offer a slightly more optimistic scenario that gives at least one of the planets, TRAPPIST-1e, the chance at sustaining an ocean on its surface. The research was published in The Astrophysical Journal.

The TRAPPIST-1 system is incredibly special because it's packed with seven planets, and three of them are near what we consider to be the habitable zone of the central star. However, scientists think the star had an extremely intense early phase that would likely have scorched the planets, stripping their atmosphere and moisture away long ago.

In studying each of the individual planets, the fourth most distant from the star caught the attention of scientists. Using advanced models to predict the fate of each world, the research team arrived at the conclusion that TRAPPIST-1e may have escaped the fate of its peers and could still support an ocean on its surface.

The University of Washington, which led the work, breaks down the findings like so:

• TRAPPIST-1 b, the closest to the star, is a blazing world too hot even for clouds of sulfuric acid, as on Venus, to form.
• Planets c and d receive slightly more energy from their star than Venus and Earth do from the sun and could be Venus-like, with a dense, uninhabitable atmosphere.
• TRAPPIST-1 e is the most likely of the seven to host liquid water on a temperate surface, and would be an excellent choice for further study with habitability in mind.
• The outer planets f, g and h could be Venus-like or could be frozen, depending on how much water formed on the planet during its evolution.

Going forward, the paper could act as a roadmap for further study of the planet and its brethren, especially after more advanced exoplanet hunters like the James Webb Space Telescope begin their work in the years to come.