Hycean planets rich in hydrogen
Discovering these oceanic planets is a great opportunity to improve our knowledge of life. While it was often thought that life could only appear on planets very similar to ours, scientists now assume that it could also evolve on planets very different from Earth.
With this reasoning, a group of astronomers from the University of Cambridge investigated the conditions that could exist on planets much larger than our exoplanets. It is larger and bulkier than Earth and is generally classified into two categories. Giants are rocky planets up to 1.7 times the size of Earth. A small Neptune surrounded by gas and covered with a liquid ocean.
These planets are unknown, as there are none in our solar system, and they are generally not case studies looking for life. However, according to this team of Cambridge researchers, some miniature Neptunes can create favorable conditions for the emergence of life. People with a hydrogen-rich atmosphere above an ocean of liquid water seem to be the most interesting subject. Scientists call them hickey or hickey planets.
These planets are uniquely different from Earth. They are on average 2.6 times larger. It is surrounded by a very dense hydrogen atmosphere which causes a significant global warming effect.
According to Cambridge researchers, this small Neptune is found near the Sun. This proximity will cause the planet to rotate synchronously with its star. She always gave him the same face, like the moon and the earth, resulting in extreme temperatures. The part facing the star would be too hot for all life to exist and would be subject to intense radiation from the star, despite the thick hydrogen atmosphere. On the other hand, this very hot part of the ocean would transfer enough heat to the face of the cooler night to make it temperate and allow life to flourish.
Searching for traces of biometrics
According to a team from the University of Cambridge, these Hycean planets will be prime places to look for signs of life likely present in microbial form and at depths dependent on the specific surface conditions of these planets. Many researchers believe that this life must exist in the depths where conditions similar to those found in hydrothermal vents in the abyssal depths of the Earth prevail.
But how will astronomers begin to discover the presence of life on these planets located 150 light years from Earth? By searching for the presence of vital fingerprints in the atmosphere of planets. These biosignatures, which are in some ways chemical traces of biological processes, are oxygen, ozone, methane, nitrous oxide, methyl chloride and dimethyl sulfide.
Unfortunately, this identification is not yet possible, and we will have to wait for the launch, currently scheduled for December 2021, of the James Webb Space Telescope (JWST). He will be responsible, among other things, for analyzing the infrared spectrum of an exoplanet passing in front of its star. By analyzing the different wavelengths of the spectrum, scientists can infer the composition of the atmosphere of an exoplanet.
Astronomers already have eleven candidates to study. They are mostly located at distances of 35 to 150 light-years and all orbit red dwarf stars. Among them, the exoplanet K2-18b is the first planet to be subjected to spectroscopic analysis by the James Webb Space Telescope. This exoplanet, initially discovered by the Kepler telescope, is located 110 light-years away and is eight times the mass of Earth with a volume 2.6 times larger. It is in the habitable zone of the sun with liquid water on the surface and most likely water vapor.
Another candidate, TOI-1231b is a recently discovered exoplanet orbiting 90 light-years from Earth. It has a mass of 15.5 times that of Earth and a volume of 3.65 times greater. It was detected by the TESS telescope.
Astronomers at the University of Cambridge have discovered exoplanets that may be a major breakthrough in the search for extraterrestrial life. In what form exactly? We basically have no idea, although it’s very likely that it’s in some simple form. This is why the commissioning of the JWST Space Telescope is eagerly awaiting astronomers around the world.
>> Read also: “Exoplanets: they changed everything!”
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