2023-06-23 02:00:51
The James Webb Space Telescope (JWST) analyzed the rocky exoplanet TRAPPIST-1 c, one of the most attractive for astrobiologists and astronomers for its stellar conditions. Until recently, the planet was a top candidate on the list of habitable planets, but the latest JWST data has ruled it out and, along with it, countless other planets with the same circumstances.
TRAPPIST-1 c is one of the seven planets that orbit a red dwarf star, and one of the four planets in that solar system that are in a potentially habitable zone, where they receive the correct radiation and gravitational force to create a friendly atmosphere for life.
The planet that the JWST studied is known as the ‘twin’ of Venus, since it is similar in size and the radiation it receives from its sun would be the same. The telescope was pointed at the planet and, with the help of its infrared instruments, managed to measure its daytime temperature. The results were not encouraging. TRAPPIST-1 c had a temperature of 107 degrees Celsius on its bright side.
The TRAPPIST system is located 40 light years from Earth. (Photo: artist rendering by NASA)
The exoplanet is much colder than, for example, Venus whose temperature is calculated at 453°C. The reading, along with other characteristics such as the amount of light the planet reflects, provides enough evidence for scientists to determine that TRAPPIST-1 c does not have an atmosphere. Habitable planets must assume an atmosphere dense enough to create a capsule for weather and other atmospheric phenomena.
“Our results are consistent with the planet being a bare rock with no atmosphere, or the planet having a really thin CO2 atmosphere. If the planet had a thick CO2 atmosphere, we would have observed a very shallow secondary eclipse (the technique with which they calculated the brightness of the light). This is because C02 would absorb all the light of 15 microns, so we would not detect any coming from the planet” explained Sebastian Zieba, the main author of the study published in the portal Nature.
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With the new observations, models were made to determine the possible chemistry of the planet. The scientists in charge of the analysis concluded that TRAPPIST-1 c never had enough water (since its formation) to be considered habitable.
Planets like the one recently analyzed are the most common to exist within red dwarf habitable zones. For the scientists, the JWST review and its conclusions “definitely reduce the number of planets that could be habitable.”
A few months ago, scientists also ruled out TRAPPIST-1 b, from the same solar system, as a habitable exoplanet. Now only two others remain that are likely to be habitable on a star 40 light-years from Earth.
Red dwarf stars are the most common in the galaxy. They are ‘cold’ bodies, with a surface temperature between 2,000°C and 3,000°C. They are small and have up to a third of the mass of our Sun. Scientists believe that if there are any habitable planets in the universe, they must be orbiting red dwarf stars.
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