four questions about Trappist-1, this planetary system that could host life 39 light years from Earth

four questions about Trappist-1, this planetary system that could host life 39 light years from Earth

four questions about Trappist-1, this planetary system that could host life 39 light years from Earth

Enthusiasm is highest within the scientific community. The James Webb Telescope began observing the system of seven exoplanets discovered in 2017. This set of Earth-like planets located around a star could very well meet the prerequisites for the possible presence of life forms. Franceinfo explains why, with Trappist-1, researchers have their heads in the stars more than ever.

1What is Trappist-1?

In 2017 the aThis is discovered by an international team led by Belgian researchers from the University of Liège the existence of seven exoplanets, all close to the size of the Earth. They orbit Trappist-1, a dwarf star located 39 light years from our solar system. Why “Trappist”? In homage to the telescope of the same name located in Chile that made this observation … and also in a nod to a Belgian beer.

“Trappist-1 is a red dwarf, when our Sun is a yellow dwarf”, explains to franceinfo Philippe Delorme, researcher at the Institute of Planetology and Astrophysics of Grenoble (IPAG). It is ten times less massive than our star. red dwarfs “are the smallest and faintest stars; about 80% of the stars are red dwarfs, but none are visible to the naked eye from Land”Futura Sciences details.

2What are the specificities of these planets?

The seven planets (baptized b, c, d, e, f, g and h) are rocky and non-gaseous, like Jupiter or Saturn. These seven planets are very close to their star. “If we were to confront our solar system, it is as if they were in the orbit of Mercury”, explains to franceinfo Marc Ollivier, astronomer and director of the Institute of Space Astrophysics of Orsay (Essonne). This means they revolve around Trappist-1 in a very short time, between a day and a half, for the closest, and 19 days, for the farthest, reports The Parisian.

Another feature: this system is located less than forty light years from Earth. Knowing that one light year equals about 9,500 billion km, Trappist-1 is therefore about 370,000 billion km from us.

“It is the very close suburb of the Earth, when we know that our galaxy, the Milky Way, measures 100,000 light years.”

Marc Ollivier, astronomer and director of the Institute for Space Astrophysics

to franceinfo

Finally, these planets are aligned, that is, they lower the brightness of the star when they make their revolution, “which makes them easier to study”adds Philippe Delorme.

3Why does this system excite the scientific community?

Several thousand exoplanetary systems have already been detected in space since the first in 1995, but this arouses a particular enthusiasm. “There is a conjunction between the presence of planets in the habitable zone of a star and James Webb’s ability to observe”points out Philippe Delorme. “It is the system physically closest to the Earth, with planets that resemble it and are aligned”He adds.

Three of the planets, e, f and g, precisely The Parisianare therefore found in the “living area” of Trappist-1, i.e. neither too close nor too far from it, offering adequate temperatures for liquid water to exist on their surface.

“It doesn’t mean there is life, but it does mean it’s not foolish to think so.”

Philippe Delorme, researcher at the Institute of Planetology and Astrophysics of Grenoble

to franceinfo

The system “Trappist-1 is uniqueconfirms to AFP Olivia Lim, doctoral student at the University of Montreal. All, or almost all, the conditions that are favorable for us to search for life outside our solar system “.

However, if there is life, it could be very different from what we know on Earth, because the rotation of the planets on themselves and their revolution around Trappist-1 could be synchronous. “As for our Moon, for which we always see the same face, the star would only see one face of the planets, explains Marc Olivier, then it would be the eternal day for this side and the eternal night for the other. “

4Why is James Webb changing the game?

If the Trappist telescope in Chile could find them, it couldn’t go much further. James Webb can. “VS ‘it really is the perfect tool to study the Trappist-1 planetary system, a star that emits mainly in the infrared, being James Webb an infrared space telescope “affirms a Parisian Michele Gillon, astronomer at the University of Liège. Thanks to its more sophisticated tools, it will be able to determine if these planets have an atmosphere and, if so, its composition.

How ? Observing the planets as they pass around the star, that is, as they pass in front of it, from our point of view. With each passage of a planet in front of Trappist-1, James Webb will be able to observe the star’s decrease in brightness, but also to shoot down its light, by means of spectroscopy, just as a rainbow breaks sunlight into different colors. .

By multiplying the observations, James Webb will then be able to identify the possible presence “of traces of biomarkers, slip Philippe Delormethat is, the presence of a gas or a combination of gases that we would detect in an atmosphere, which we cannot explain by anything other than the presence of a form of life “.” The presence of methane and oxygen, as on Earth, would be really exciting “concludes the scientist.

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