Hycean Planets: Could they harbour life?
- Dev
- Sep 19, 2021
- 3 min read
Hello and welcome to Astronosmia! In this blog article, I will be talking about the newest trend in astrobiology - Hycean Planets! We will be looking at what hycean planets are, hycean planet discoveries and could they harbour life? Sit back tight and get ready for a journey to Hycean Planets!
CONTENTS
1) WHAT ARE HYCEAN PLANETS?
2) HAVE ANY SUCH PLANETS BEEN DISCOVERED?
3) COULD THESE PLANETS HARBOUR ALIEN LIFE?
1) WHAT ARE HYCEAN PLANETS?
Hycean Planets are a new category of exoplanets that are speculated to be hot water worlds (ocean planets) with hydrogen-rich atmospheres which may be capable of harbouring life. The term "hycean" is most likely a mix of the two words, "hydrogen" and "ocean".
DISCOVERY
The first notion of Hycean Planets was given by astronomers from the University of Cambridge in August 2021.
"Hycean planets open a whole new avenue in our search for life elsewhere" - Dr Nikku Madhusudhan
These planets are speculated to include both Super-Earths and mini-Neptunes. Remember we talked about both of these worlds in the previous article? This means that these planets could be between the sizes of Earth and Neptune or Uranus. The temperatures on these planets could be above 200 degrees celsius (473 Kelvin; 392 degrees Fahrenheit).
Astronomers from the University of Cambridge have constructed something called the Hycean habitable zone which examines the habitable zones of M-type to Sun-like (G-type) stars. According to astronomers, the habitable zones are far wider than the habitable zone of terrestrial planets.
So, have we discovered any such planet so far? Let's see...
2) HAVE ANY SUCH PLANETS BEEN DISCOVERED?
Exoplanets like K2-18b and TOI 1231 b could be hycean worlds. Since this is a relatively new category of exoplanets, more research is needed to classify these planets and possibly discover newer ones.
The James Webb Space Telescope (JWST) will probably reveal more about these worlds in the upcoming years as the search for extraterrestrial life intensifies.
3) COULD THESE PLANETS HARBOUR LIFE?
Given the characteristics of Hycean Planets, we could speculate whether if these planets could host life. The temperatures of these planets are thought to be around 227 degrees celsius (500 Kelvin; 440.6 Fahrenheit). Astrobiologists when looking for potentially habitable exoplanets look at the possible temperatures for liquid water to exist. They also look at the habitable zone of their parent stars to determine their habitability. That being said, the possibility of life in hycean worlds is likely given that these planets are most likely ocean planets or planets covered largely in water and a wider habitable zone.
In this graph, two other categories of hycean worlds could be seen. These are the habitable zones of Dark and Cold Hycean planets.
Dark-Hycean planets
These planets are thought to be closer to their parent stars resulting in them being tidally locked. Hence, one side of these planets will be facing permanent brightness which will be experiencing extreme temperatures. Whereas, the other side of these planets would be experiencing permanent darkness with significantly cooler temperatures. The possibility of life looks far more on the dark side.
Cold-Hycean planets
These planets are thought to be too far from their parent stars resulting in them being having really cool temperatures and receiving little radiation from their parent stars as compared to Dark-Hycean planets. Chances of life on these planets could be less than hycean planets. Only time will tell that...
REFERENCES
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