This is not the first time that astronomers have discovered an exoplanet around a triple star. But the one they named LTT 1445Ab appears in a configuration that could be particularly interesting in the context of the realization of a spectroscopic study of its atmosphere by the future James-Webb space telescope.
In our universe, multiple star systems are not uncommon. They are often composed of three stars gravitationally related to each other. And researchers at Harvard (United States) have just discovered, at the heart of such a system, a new exoplanet that particularly attracts their attention.
This is thanks to a discovery made possible by Tess (Transiting Exoplanet Survey Satellite), the small telescope space of Nasa spent searching for exoplanets. How? By detecting the gradual attenuation of the light of a star due to the passage of a planet between it and our Earth. This star is LTT 1445. More exactly, a system of three red dwarfs that is about 22.5 light-years away from us.
The new exoplanet has been dubbed LTT 1445Ab because it revolves around the main star of the system and is the second planet to be discovered in this system. “From the surface of this planet, we can see three suns in the sky, but two of them appear small,” says Jennifer Winters, an astronomer at Harvard.
According to researchers, the radius of this planet is no more than 1.35 times that of the Earth. It would be up to 8.4 times heavier than our planet. However, the chances of it being able to shelter life seem weak. Indeed, LTT 1445Ab revolves around its star in only 5.36 Earth days. It is so close that the temperature on its surface would be of the order of 155 ° C.
Nevertheless, astronomers believe that it has an atmosphere. However, when a planet with an atmosphere passes in front of its star, it does not only decrease its brightness. It also modifies it, according to the composition of the atmosphere in question.