Super-Earth LP 890-9 c is within the habitability zone of its star, a quiet and "soft" red dwarf. According to the authors of the discovery, it is the second on the list of the most promising candidates for the presence of life outside the solar system.
The star, located at 114 light-years, found two exoplanets from the class of super-Earths. One is within the "habitable zone," a region where temperatures are moderate enough to allow liquid water to persist on the planet's surface, which is considered a key condition for the emergence of life.
The vast majority of known exoplanets are detected by the transit method, by a faint change in the radiation of the parent star at times when the planet passes between it and us. Therefore, most of the found exoplanets are quite large and are gas giants, the signal from which is quite easy to detect, but which it is difficult to call at least potentially inhabited.
In order to search for more habitable worlds at the Paranal Observatory, the SPECULOOS project is being implemented. As part of this program, the glow of about 1700 red dwarfs is monitored. Such stars are rather dim and cold, and if there are potentially habitable planets near them, they must be in very tight orbits, which makes them easier to detect by the same transit method.
One such find is described in a new paper authored by a large international team of scientists. The object of their observations was the ultracold dwarf LP 890-9 (TOI-4306), located 104 light years from the Sun. Two exoplanets of the super-Earth class, LP 890-9 b and LP 890-9 c, were discovered nearby. The former is about 30 percent larger than Earth and is 50 times closer to the star than we are to the Sun, making a complete annual revolution in 2.7 days. LP 890-9 is slightly larger and farther away: a year there lasts about 8.5 days.
Both planets are much closer to their star than Mercury is to the Sun. However, the star is also far from as hot and bright as ours, so the temperature on LP 890-9 b and LP 890-9 c remains fairly moderate. LP 890-9 is 6.5 times smaller than the Sun and half as hot, not even reaching 2,900 kelvin. As a result, its second planet, although ten times closer to it than Mercury to the Sun, remains within the habitability range of the star.
The star LP 890-9 itself is relatively young for a red dwarf, its age does not reach seven billion years. It is characterized by low activity, which makes its planets even more suitable for life - at least in theory. According to the authors of the paper, LP 890-9 c can be called "the second most suitable for life earth-like planets within the habitable zone of its parent star. Only the worlds of the famous TRAPPIST-1 system look more favorable.
The close proximity and ease of observation make the potentially habitable planet LP 890-9 a convenient target for the James Webb Space Telescope to investigate its atmosphere. Perhaps such work will be done in the near future. For now, we can say that since LP 890-9 c is closer to the inner boundary of the habitable zone, its atmosphere should contain large amounts of water vapor.
