The James Webb Space Telescope has started looking at the most tantalizing candidates for life elsewhere in the universe: a group of exoplanets in the star system known as TRAPPIST-1.
It means that in the next few years, astronomers can expect a lot of data from a group of planets outside our solar system that help answer the age-old question: Are we alone in the universe?
Webb has stunned the world in recent weeks after POT launched his first batch of proper observations which included the deepest infrared image of the universe ever taken.
While the telescope’s stunning and colorful images of distant cosmic objects capture the public imagination, it could be easy to overlook the wealth of raw data the telescope has been and will continue to collect.
NASA/JPL-Caltech
Almost immediately after he was able to make scientific observations, Webb began studying the TRAPPIST-1 system on a priority basis. TRAPPIST-1 is a red dwarf star located about 12 parsecs (39 light-years) from our sun and has interested astronomers since it was discovered in 2017.
That’s because TRAPPIST-1 was found to have at least seven rocks. exoplanets—planets that exist outside the solar system—orbit it with sizes and masses similar to that of Earth. Additionally, initial observations suggested that some of the planets might have temperatures low enough to hypothetically support the presence of liquid water.
“There are other planets that are terrestrial or temperate or both, but they are usually too far away or around a star that is too big to allow us to really study them,” said Julien de Wit, assistant professor in Earth, Atmospheric and Planetary. Department of Science at the Massachusetts Institute of Technology and part of the team that discovered the TRAPPIST-1 system, said news week.
“So these are the only windows we have into possibly the atmosphere of other habitable terrestrial planets, and that’s what’s really special about them.”
However, due to technological limitations, we have so far been unable to determine a critical characteristic of these planets: whether or not they have atmospheres. That is, until Webb entered the picture.
“The question we want to answer now is do they have an atmosphere? If they do have an atmosphere, then things are going to get very exciting,” said Michaël Gillon, an exoplanet researcher at the University of Liège in Belgium, who led the team that discovered the system. TRAPPIST-1.
He said news week: “You really need a very large telescope that is far from Earth, that you can monitor for hours or days if necessary, and that operates over a wide wavelength range in the infrared [spectrum], because this is where all the molecular spectroscopic features we are looking for are found. And James Webb is exactly what I’m talking about.”
For de Wit, the technological step forward made with Webb can hardly be overstated. “In terms of information content, we’re going from listening to radio to having television,” he said.
split light
The method scientists will use to determine whether the TRAPPIST-1 planets have atmospheres or not. It’s called transit spectroscopy.. It works by collecting sunlight passing around a nearby planet and splitting this light into a spectrum, much like a prism splits white light into a rainbow.
If that sunlight passed through a planet’s atmosphere on its way to Earth, then there will be telltale signs in the spectrum of that light.
“So you have fingerprints of the chemical signature of the atmosphere showing up in your data and your spectroscopic data,” Gillon said.
NASA GSFC/CIL/Adriana Manrique Gutierrez
The investigation will be carried out in stages. First, Webb astronomers will determine whether any of TRAPPIST-1’s planets actually have an atmosphere, a breakthrough in itself.
Second, work will begin to find out what each of these atmospheres is made of. A process de Wit described as “like peeling an onion”.
“One thing worth noting is that something may be easily detectable just because it has very strong features, but it could be a very, very small amount,” he added. “So we’ll start finding molecular features, that’s great. But then the next step would be to have enough data that we can start discussing how much of this, of that, and then we can even start extracting information about the temperature, in function of altitude, and pressure”.
Webb’s team could then begin to infer details about surface conditions and processes that might have led to the presence of those atmospheric components in the first place.
“It’s like your favorite TV show, and you have to wait a week to get to the next episode,” de Wit said. “In this case, you may have to wait a year to get the next episode.”
have a gas
There are many atmospheric components that would be of interest to scientists studying the TRAPPIST-1 planets (water vapor might be one of the first to think), but for Gillon, methane will be the main one.
“We know that methane has a very short shelf life,” he said. “In such an atmosphere, their molecules disappear very quickly. So if there are large amounts of methane in the atmosphere of one of these TRAPPIST-1 planets, with the atmosphere also rich in CO2 or ozone, it would mean that there was a very high amount of methane. “. great source of methane And we don’t know of many abiotic sources, but we do know that life can produce methane.
“We think that before the Earth’s atmosphere was very rich in oxygen, thanks to increased photosynthesis, methane was abundant in the Earth’s atmosphere because there were some bacteria that produced a lot of methane at that time.
“So if we do detect methane, that will be very exciting.”