Scientists have discovered two “super-Earth” exoplanets, one of which is in the habitable zone of its star. This means that liquid water can exist on its surface.

The planet, known as LP 890-9c or SPECULOOS-2c, lies around a red dwarf star about 100 light-years from Earth in the constellation Eridanus. Red dwarf stars are cooler than our Sun and are more readily abundant in our Milky Way, making up about 80% of the population astronomers know of.

Of the potentially habitable terrestrial planets currently known to astronomers, LP 890-9c appears to be the second most suitable target, according to its discoverers. It was found by chance as scientists verified their initial discovery of another exoplanet around the same star, called LP 890-9/TOI-4306/SPECULOOS-2. It is the second coolest star found to host planets after the famous TRAPPIST-1 star system, which hosts up to seven planets and has been placed under “Solar System 2.0”.

Fortunately, TESS is limited in what it can detect, so feedback requires double checking. It detects exoplanets by detecting a slight dimming of a star as a planet – or its shadow – crosses its surface. Dr Laetitia Delris, FNRS postdoctoral researcher at the University of Liège, Belgium and lead author of the study said. “This tracking is especially important in the case of relatively cool stars, like TOI-4306, which emit most of their light in the near-infrared and have somewhat limited TESS sensitivity. »

Could the LP 890-9c really be habitable? This is unknown. It’s a “super-earth,” but don’t assume it’s like the slightly larger Earth. LP 890-9c is probably rocky and about a third larger than Earth, but it only takes 8.5 days to orbit its star. Because it orbits a star much cooler than our Sun to begin with.

“Although this planet orbits close to its star, at a distance about 10 times shorter than that of Mercury around our sun, the amount of stellar radiation it receives is still small and could allow liquid water to exist on the surface of the planet,” said Francisco J. The researcher at the Institute of Astrophysics of Andalusia and one of the co-lead authors of the research, “provided that the atmosphere is sufficient. “This is because the star LP 890-9 is about 6.5 times smaller than the Sun and its surface temperature is half that of our star. This explains why LP 890-9c, despite being closer to its star than Earth to the Sun, may still have conditions suitable for life. »

Before announcing that this “super-Earth” is similar to Earth, other observations must be made, in particular with the James Webb Space Telescope (JWST), which could help researchers examine its atmosphere – if any. has one.

The study authors believe that this exoplanet could be ripe for the discovery of JWST’s atmosphere. “LP 890-9c is located near the inner limit of the habitable zone, and therefore could have a particularly rich water vapor atmosphere, which would enhance atmospheric signals,” Delreese said. I consider the discovery of LP 890 -9c a unique opportunity to learn more about the exact location of the inner limit of the star’s habitable zone.

However, the habitable zone around a star where liquid water could theoretically exist – between the very distant “snow line” and the very near “boiling region” – guarantees nothing. “Our neighbor planet Venus is, so to speak, a carbon dioxide-rich pressure cooker at almost 500 degrees Celsius, close to this habitable zone around the Sun,” said Dr Robert Wells of the University. of Bern and the National Center for Climate Research (PRN) . PlanetS and co-author of the study.

Astronomers discover a planet where you could live to be 29,649 years old

Scientists have discovered two super-Earth-like planets, located about 100 light-years from our own planet (about 946 trillion kilometers). Both planets orbit a small, cool star, called TOI-4306, or SPECULOOS-2.

Two exoplanets detected, including one particularly intriguing

Researchers from the University of Liège used their ground-based SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) telescopes to confirm and characterize this planet, but also to probe the system at depth in search of other planets that would have could have been missed by TESS. The observation: this planet, which is about 30% larger than Earth, completes an orbit around its star in just 2.7 days.

On the other hand, these observations made it possible to detect a second one, hitherto unknown: LP 890-9c or SPECULOOS-2c. It is approximately 40% larger than Earth. On the other hand, it displays a very different revolution period, 8.5 days. Of course, living to be 29,649 would be pure science fiction; however, scientists believe that it is in a circumstellar habitable zone

LP 890-9c also orbits at a distance 10 times shorter than that of Mercury around our Sun. The amount of stellar irradiation it receives is still small. The presence of liquid water on its surface would also be a possibility. Provided there is sufficient atmosphere.