Astronomers might be close to confirming the presence of an Earth-like atmosphere on an exoplanet for the first time, if more detailed analyses verify preliminary observations from the James Webb Space Telescope.
Four observations performed in 2023 with the Webb telescope were unable to rule out the presence of an atmosphere, prompting optimism.
(Earth similarly lost its primordial, primary atmosphere early on but then built a secondary one; astronomers hope that TRAPPIST-1 e could have done the same.)
Gillon, who led the original discovery of the TRAPPIST-1 system, was not part of the recent study.
TRAPPIST-1 e is the most promising of the seven planets for hosting an Earth-like atmosphere, according to Agol.
If more thorough examinations validate early findings from the James Webb Space Telescope, astronomers may be on the verge of confirming for the first time that an exoplanet has an atmosphere similar to Earth.
The planet is a member of the TRAPPIST-1 planetary system, which was named after their favorite beer by five Belgian astronomers who discovered it in 2016. The system is located about 40 light-years from Earth. Since then, the system has been the subject of extensive research.
“It’s as alien as it gets as a planetary system,” astronomer Néstor Espinoza of the Space Telescope Science Institute in Baltimore said. With at least seven rocky planets orbiting it, the star is minuscule, about the size of Jupiter. Three of those are in the region known as the habitable zone, which is so close to the star that liquid water could exist there if it had an atmosphere. “”.
The study, which was published last week in The Astrophysical Journal Letters, focused on TRAPPIST-1 e, the system’s fourth planet from the star. When four 2023 Webb telescope observations failed to rule out the existence of an atmosphere, hope was aroused.
“We cannot conclude that (this planet) lacks an atmosphere based on the first four observations, so the dream is still alive — it could still have an atmosphere,” Espinoza stated. “That’s really exciting because we do have a follow-up program of 15 more observations.”. “.”.
Espinoza stated that TRAPPIST-1 e is regarded as one of the best candidates for liquid surface water, but the Webb telescope has only been able to rule out any atmosphere on TRAPPIST-1 b, the innermost planet. The other six planets are still up for debate.
When Espinoza discussed the prospect of finding atmospheres on distant planets, he said, “three years ago, before the launch of James Webb, these kinds of studies were science fiction.”. Now, I’m fairly certain that we’ll be able to observe the potential atmosphere of TRAPPIST-1 e and determine whether it has an atmosphere similar to Earth. “.”.
searching for warning indications.
Comparable in size to Earth, TRAPPIST-1 e orbits its star every six days, which is a far faster orbital period than Earth’s orbit around the sun. All of the planets are near the star, which is much smaller than our sun. According to Espinoza, “all the planets and their orbits would fit within the orbit of Mercury if you could magically bring the TRAPPIST-1 star to our solar system.”. “.”.
Astronomers wait for a planet to pass in front of its star in order to detect any slight variations in the starlight that pass through in order to search for an atmosphere. As they study the chemical makeup of an atmosphere, they look for telltale signs of it.
Astronomers were able to rule out the possibility of a primary, hydrogen-based atmosphere on TRAPPIST-1 e with the four transits seen by the Webb telescope in 2023. This atmosphere was probably blown away by the star’s massive radiation emissions. Astronomers believe TRAPPIST-1 e may have accomplished the same thing as Earth, which lost its primordial, primary atmosphere early on before creating a secondary one. ().
Another study, which was also released last week in The Astrophysical Journal Letters, describes this situation in detail. It indicates that the planet’s atmosphere is more likely to be nitrogen-heavy, more akin to Earth and Saturn’s icy moon Titan, rather than carbon dioxide-rich like that of Venus and Mars.
Sara Seager, a planetary science professor at the Massachusetts Institute of Technology and coauthor of both studies, said in a statement, “TRAPPIST-1e is still one of our most compelling habitable-zone planets, and these new results take us a step closer to knowing what kind of world it is.”. “Our attention is drawn to the scenarios that are still possible by the evidence that points away from atmospheres similar to those of Venus and Mars. “.”.
Espinoza stated that his team has already finished two-thirds of the new round of 15 observations and intends to complete the remaining 15 by the end of the year. In order to detect certain chemical signatures of gases like methane, which is linked to life on Earth, the team may need to conduct additional Webb telescope observations if they discover indisputable evidence of an atmosphere.
According to Espinoza, the confirmation of an atmosphere would be revolutionary. The question of whether or not these red dwarf systems are capable of supporting an atmosphere would be resolved, he said. The vast majority of stars in the universe are actually red dwarfs. Therefore, it can occur anywhere if it can there. Life’s potential simply multiplies. “.”.
He added that the outcome would still be thrilling even if an atmosphere was disproved because it would further enhance the uniqueness of life on Earth. It would also pave the way for future studies that use telescopes even more potent than Webb, which are still in the planning stages, to examine exoplanets orbiting yellow dwarf stars like the sun.
Exciting but unfinished outcomes.
Michaël Gillon, research director of the Astrobiology Research Unit at the University of Liège in Belgium, expressed his excitement about the first James Webb results for TRAPPIST-1e. Gillon, who spearheaded the initial identification of the TRAPPIST-1 system, was not involved in the most recent investigation.
In an email, he continued, “The data are not yet conclusive, but they prove that JWST has the power to detect an Earth-like atmosphere if it exists.”. We are genuinely on the verge of finding an atmosphere around a potentially habitable rocky exoplanet for the first time in history. “”.
Similar to the terrestrial planets in our solar system, the planets in TRAPPIST-1 have a variety of conditions. In order to keep the water from freezing on the surface or sublimating to space, they need an atmosphere, according to Eric Agol, a professor in the University of Washington’s astronomy department. These conditions make them potential hosts for surface liquid water. Agol is working with Espinoza and his colleagues on the new set of observations, but he was not involved in the study.
According to Agol, of the seven planets, TRAPPIST-1 e has the best chance of having an atmosphere similar to Earth.
He continued in an email, “The results are intriguing, but they are not yet complete.”. The current study hasn’t changed my mind about whether or not TRAPPIST-1 e has an atmosphere similar to Earth. “”.
In a recent study published Wednesday in The Astrophysical Journal Letters, Howard Chen, an assistant professor of space sciences at the Florida Institute of Technology, described computer simulations that showed TRAPPIST-1e sits precisely at a “tipping point” between opposing states. According to its past, the planet may turn out to be either very dry or water-rich: “That means both ‘bare rock’ and ‘atmosphere-bearing’ scenarios remain physically plausible,” he continued in an email. The new research did not involve Chen.
TRAPPIST-1e might have formed as a wet, ocean-covered planet, he concluded, or as a desert world like its inner neighbors. “Our simulations predict that ambiguity exactly, but JWST’s current data cannot yet distinguish between those scenarios,” Chen stated. “The next few JWST (observations) could yield a dramatic revelation because TRAPPIST-1e can plausibly be either very dry or very wet.”. “.”
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