Two "super-Earth" planets are located around a small, cool star 100 light-years away from Earth.
The famous TRAPPIST-1 is the second-coolest star to host planets. This discovery is the subject of a upcoming publication.
The system's inner planet is 30% larger than Earth and can be seen in just over three days. The first planet was initially identified as a possible planet candidate by the TESS space mission. One of the telescopes that is operated by the University ofBirmingham confirmed this candidate. Researchers used telescopes to look for planets that would have been missed by TESS.
"TESS searches for exoplanets using the transit method, by monitoring the brightness of thousands of stars simultaneously, looking for slight dimmings that might be caused by planets passing in front of their stars."
A follow-up with ground-based telescopes is often necessary to confirm the planetary nature of the detected candidates.
This follow-up is important in the case of very cold stars, such asLP 890-9, which emit most of their light in the near-IR and for which TESS has a limited sensitivity.
Thanks to cameras that are very sensitive in the near-IR, the telescopes of theSPECULOOS project are able to see this type of star with high precision.
Michal Gillon from the University of Li says that the goal of the project is to find planets transiting some of the smallest and cooler stars in the solar neighborhood. The strategy is motivated by the fact that such planets are well suited to detailed studies of their atmospheres and to the search for chemical traces of life with large telescopes.
The observations of LP 890-9 gathered bySPECULOOS proved fruitful as they not only confirmed the first planet, but they were critical for the detection of a second planet. The second planet is roughly the same size as the first but has a longer period of time on it. The MuSCAT3 instrument in Hawaii has confirmed that the planet is in the "habitable zone".
A planet with the same geological and atmospheric conditions as Earth would have a surface temperature that would allow water to remain liquid for billions of years. We can observe more and find out if the planet has an atmosphere, and if so, assess its habitability.
The next step will be to study the atmosphere of this planet, for example with the JWST, for whichLP 890-9c appears to be the second-most favorable target among the potentially habitableTerrestrial planets known so far.
Professor Triaud said that it was important to detect as many temperateterrestrial worlds as possible to study the diversity of exoplanet climates.
More information: Two temperate super-Earths transiting a nearby late-type M dwarf, Astronomy and Astrophysics (2022). DOI: 10.1051/0004-6361/202244041 Journal information: Astronomy & Astrophysics
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