Virtually from its first day on the job, the James Webb has taught us its ability to observe exoplanets up close. This allows us to know more about some of those who, at best, knew about their existence. And that is what he has recently done with the planet TRAPPIST-1b. He has been able to study it closely to the point of discovering something that is not really good news: probably, it has no atmosphere.
Actually, TRAPPIST-1b is not a good candidate for harbor life. But yes, some of his neighbors are. Specifically, there are at least three that are in the habitable zone of their star. But to support life, exoplanets must have an atmosphere. And if this one doesn’t have it, it’s possible that the others don’t either.
It is only an assumption, although it is true that it reduces the hopes of finding life in these and many others. Earth-like exoplanets. That does not mean that you have to stop studying them, far from it, but it is somewhat discouraging.
James Webb and his ability to detect the atmosphere of exoplanets
The James Webb Space Telescope has a great ability to detect changes in infrared light. And this, among many other functions, is useful for studying the atmosphere of exoplanets.
Basically, in the same way that exoplanets are detected by changes in the light of a star as they transit around it, a telescope like the James Webb can detect if they have an atmosphere during a secondary eclipse. That is, when the planet passes behind its star. At that point, the atmosphere would cause a redistribution of infrared radiation emitted from the planet. However, when the telescope looked at TRAPPIST-1b, none of this happened. Therefore, it is concluded that, with great probability, there is no atmosphere around it.
Given the age of TRAPPIST-1b, it has had enough time for an atmosphere to build up around it. Therefore, the conclusion of the authors of this research, published now in Nature, is that its own star has been able to destroy it. This is because TRAPPIST, the star around which this and other exoplanets revolve, is a red dwarf. These types of stars have a great tendency to explode, so in their outbursts they may have destroyed the atmosphere of their closest planets. Including those in the habitable zone.
Should we lose all hope?
this star is pretty colder than our sun. Even so, given the proximity of TRAPPIST-1b, it receives four times more radiation than our Earth. It is less than that received by Mercury, the first planet in our planetary system, but more than Venus, which is the second. Therefore, without an atmosphere that stops part of that radiation, life could not proliferate in it.
Even so, there has never been any hope of finding life on this planet, since it lies outside the habitable zone. That is, the area that is at the ideal distance from the Sun so that there can be liquid water, not solid or gaseous. And that, in addition, the temperature is neither too high nor too low.
There are at least three exoplanets from this system in that area: TRAPPIST-1e, 1f and 1g. They are rocky planets, with a mass similar to that of the Earth, so they would be good candidates to host life. Now, have the outbursts from their star been able to reach them and destroy their atmosphere? We do not know. But these results lead us to think about that possibility. And not only that. The study authors believe it could occur with many other similar exoplanet systems. It is too early to say for sure and there is no consensus among scientists, so all hope is not lost either. We will have to study more. If not here, maybe somewhere else.