Potentially habitable, Earth-size exoplanet TRAPPIST-1e may have an atmosphere, James Webb telescope hints
New research using the powerful JWST telescope has identified a planet at 41 light years which can have an atmosphere. The planet is inside the “Habitable zone”The region around a star where temperatures allow liquid water to exist on the surface of a rocky world. This is important because water is a key ingredient that supports the existence of life.
If it is confirmed by other observations, it would be the first planet of the rocky habitable zone which is also known to host an atmosphere. The results come from two new studies Posted in the magazine Astrophysical Journal Letters.
The living area is partly defined by the temperature range generated by the heat of the star. The area is located at a distance from its star where temperatures are neither too hot nor too cold (which led him on the occasion nicknamed “The Goldilocks area“).
But exoplanets (stars in orbit worlds outside our solar system) capable of hosting liquid water greenhouse. The greenhouse effect generates additional heating due to the absorption and emissions of gases in the atmosphere and will help prevent water evaporation into space.
With an international team of colleagues, we have formed the largest telescope in space, NASA JwstOn a planet called Trappist-13. We wanted to determine if this rocky world, which lies in the habitable area of its star, hosts an atmosphere. The planet is one of Seven rocky worlds Known to orbit a small, “red dwarf” star called Trappist-1.
Rocky exoplanets are everywhere in our galaxy. The discovery of abundant rocky planets in the 2010s by Kepler and Tess space telescopes has deep implications for our place in the universe.
In relation: Will the James Webb telescope lead us to extraterrestrial life? Scientists say we get closer that ever.
Most of the rocky exoplanets that we have found so far in orbit red dwarf starswhich are much fresher than the sun (generally 2500 ° C / 4,500 ° F, compared to the 5,600 ° C of the sun / 10,000 ° F). It is not because the planets around the sun -shaped stars are rare, there are only technical reasons why it is easier to find and study the planets in orbit around smaller stars.
The red dwarfs also offer many advantages when we seek to measure the properties of their planets. Because the stars are cooler, their habitable zones, where temperatures are favorable to liquid water, are located much closer to our solar system, because the Sun is much hotter. As such, a year for a rocky planet with the temperature of Earth Who orbit a red dwarf star may not be a few days a week from the 365 days of the earth.
Transit method
A way to detect exoplanets is to measure the slight twrong When the transit planetOr go ahead, his star. Since the planets in orbit around the red dwarfs take less time to finish an orbit, astronomers can observe more transits in a shorter time space, which facilitates data collection.
During a transit, astronomers can measure the absorption of gases in the atmosphere of the planet (if one has one). Absorption refers to the process by which some gases absorb light at different wavelengths, preventing it from passing. This offers scientists a way to detect which gases are present in an atmosphere.
Above all, the smaller the star, the more the fraction of its light is blocked by the atmosphere of a planet during the transit. The red dwarf stars are therefore one of the best places for us to search for the atmospheres of rocky exoplanets.
Located at a relatively close distance from 41 light years from the earth, the Trappist-1 system has drawn significant attention since its discovery in 2016. Three of the planets, Trappist-1D, Trappist-1e and Trappist-1f (the third, fourth and fifth planets of the star) are in the habitable area.
JWST led Systematic research For atmospheres on the Trappist-1 planets since 2022. The results of the three most internal planets, Trappist-1b, Trappist-1c and Trappist-1D, indicate that these worlds are probably bare rocks with thin atmospheres at best. But the planets further, which are bombed with less radiation and energetic shot of the star, could still have atmospheres.
We observed Trappist-1e, the planet in the center of the Habitable Zone of the Star, with JWST on four distinct occasions of June-October 2023. We immediately noticed that our data was strongly affected by what is called “stellar contamination” of the warm and cold active regions (similar to solar stains) on Trappist-1. This required a careful analysis to manage. In the end, it took our team for more than a year to scrutinize the data and distinguish the signal from the star from that of the planet.
We see Two possible explanations For what is happening at Trappist-11e. The most exciting possibility is that the planet has a so -called secondary atmosphere containing heavy molecules such as nitrogen and methane. But the four observations that we have obtained are not yet precise enough to exclude the alternative explanation of the planet being a naked rock without atmosphere.
If Trappist-1e had an atmosphere, it will be the first time that we have found an atmosphere on a rocky planet in the habitable area of another star.
Since Trappist-1e is firmly found in the living area, a thick atmosphere with sufficient greenhouse effect could allow liquid water on the surface of the planet. To establish whether Trappist-1e is habitable or not, we will have to measure the greenhouse gas concentrations such as carbon dioxide and methane. These initial observations are an important step in this direction, but more observations with JWST will be necessary to ensure that the Trappist-1e has an atmosphere and, in the affirmative, to measure the concentrations of these gases.
As we speak, 15 additional Trappist-11e transits are underway and should be completed by the end of 2025. Our follow-up observations use a different observation strategy where we target the consecutive transits of Trappist-1b (which is a naked rock) and Trappist-1e. This will allow us to use the bare rock to better “trace” the warm and cold active regions of the star. Any excess of absorption of gas observed only during transits of Trappist-1e will only be caused by the atmosphere of the planet.
So, over the next two years, we should have a much better image of the way in which Trappist-1e compared to the rocky planets of our solar system.
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