Skip to main content

New type of ocean-covered ‘Hycean’ exoplanet could support life

When it comes to looking for life elsewhere in the universe, we tend to be very Earth-centric: We look for planets that are similar to our own, assuming that life elsewhere will be similar to us and require similar conditions. However, a new type of exoplanet has been identified by astronomers at the University of Cambridge, and even though it is very different from Earth it could still support life.

The new class of planet is called a “Hycean” planet, meaning an ocean-covered world with abundant hydrogen in its atmosphere. The researchers believe that this type of planet could be common and as they are potentially habitable this significantly increases the possible locations to search for life outside our solar system.

 Artist's impression of a Hycean planet.
Artist’s impression of a Hycean planet. Amanda Smith

“Hycean planets open a whole new avenue in our search for life elsewhere,” said lead researcher Nikku Madhusudhan from the University of Cambridge’s Institute of Astronomy in a statement.

Recommended Videos

These planets are typically larger than Earth, at up to 2.6 times its size, and can be hotter as well, with atmospheric temperatures of up to 200 degrees Celsius. However, despite these high temperatures their oceans could still host microbial life, as suggested by another recent study into a large exoplanet with a hydrogen-rich atmosphere. This study found that there could be liquid water on the planet’s surface beneath its atmosphere. If this is true for Hycean planets as well, then the habitable zone — the area around a star where a planet must orbit for liquid water to be able to exist on its surface — could be larger for these planets than for other types of planets.

“Essentially, when we’ve been looking for these various molecular signatures, we have been focusing on planets similar to Earth, which is a reasonable place to start,” said Madhusudhan. “But we think Hycean planets offer a better chance of finding several trace biosignatures.”

Biosignatures are chemical indications of life and are one of the main ways that researchers look for life elsewhere in the universe.

“A biosignature detection would transform our understanding of life in the universe,” said Madhusudhan. “We need to be open about where we expect to find life and what form that life could take, as nature continues to surprise us in often unimaginable ways.”

The research is published in The Astrophysical Journal.

Georgina Torbet
Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…
James Webb discovers a new type of exoplanet: an exotic ‘steam world’
An artist’s conception of the “steam world” GJ 9827 d, shown in the foreground in blue.

Our solar system has a wide variety of planet types, from tiny rocky Mercury to huge puffy gas giant Jupiter to distant ice giant Uranus. But beyond our own system, there are even more types of exoplanet out there, including water worlds covered in ocean and where life could potentially thrive. Now, researchers using the James Webb Space Telescope have identified a new and exotic type of planet called a steam world, which has an atmosphere almost entirely composed of water vapor.

The planet, called GJ 9827 d, was examined by the Hubble Space Telescope earlier this year and had researchers so intrigued that they wanted to go back for a closer look using Webb. They found that the planet, which is around twice the size of Earth, had a very different atmosphere from the typical hydrogen and helium that is usually seen. Instead, it was full of hot steam.

Read more
There’s a tiny exoplanet orbiting our neighbor, known as Barnard’s star
Artist’s impression of a sub-Earth-mass planet orbiting Barnard’s star

In our local cosmic neighborhood, the nearest star is Proxima Centauri, which is part of the three-star Alpha Centauri system and known to host exoplanets of its own. But just a little further away is a single star on its own, known as Barnard's star. Recently, astronomers discovered that this star also hosts at least one exoplanet, and could host as many as four.

At just six light-years from Earth, Barnard's star is close by and has long been of interest to researchers searching for nearby exoplanets. But as a small, dim type of star called a red dwarf, no one has discovered an exoplanet here before -- though there were hints found in 2018 that such a planet might exist.

Read more
One half of this wild exoplanet reaches temperatures of 1,450 degrees Fahrenheit
webb wasp 39b dayside nightside stsci 01j2f12rm1s3n39yj938nhsf93 png

This artist’s concept shows what the exoplanet WASP-39 b could look like based on indirect transit observations from JWST and other space- and ground-based telescopes. Data collected by its NIRSpec (Near-Infrared Spectrograph) show variations between the morning and evening atmosphere of the planet. NASA, ESA, CSA, Ralf Crawford (STScI)

One of the ground-breaking abilities of the James Webb Space Telescope is that researchers can use it to not only detect distant planets but also to peer into their atmosphere. Now, new research using Webb has uncovered differing conditions between morning and evening on a distant exoplanet, the first time such differences have been observed on a planet outside our solar system.

Read more