UNITED STATES, WASHINGTON (OBSERVATORY) — Two planets at a star located very close to the Sun are very similar to the Earth and can be inhabited. Astronomers call them, perhaps, the most similar to the Earth from known exoplanets. This conclusion was made in a scientific article published in the publication Astrophysical Journal Letters by Israeli scientists.
The star of Tigarden is a red dwarf of class M. Such luminaries are very small and dim. Therefore, this star was discovered only in 2003, despite the fact that it is only 12.5 light years from the Sun. For comparison: the distance to Proxima Centauri, the nearest luminary to the Sun, is 4.2 light years.
In 2019, two planets were discovered at the star of Tigarden . According to the rules for naming exoplanets, they were called “Teegarden star b”, and “Tigarden star c”. For convenience, these names are abbreviated as TG b and TG c.
Both worlds have a mass of 1-2 earthly. On TG b, the “year” is 4.9 Earth days, and on TG c it is 11.4. This allowed astronomers to preliminary assume that these worlds are close enough to their dim sun to be inhabited.
In a new study, the temperature on the surface of these two exoplanets and the possibility of the existence of liquid water on them are calculated more carefully, taking into account the possible composition and thickness of the atmosphere.
First of all, the authors note that TG b and TG c are probably always turned to their star on one side (like the Moon to the Earth). That is, in one hemisphere – eternal day, and in the other – eternal night. This is due to the fact that they are very close to their sun.
However, this does not mean that murderous heat reigns on the day side, and mortal cold on the night side. If these worlds have a gas shell, then the winds transfer heat from the hot hemisphere to the cold. According to the authors, an atmosphere with a density of 0.3 to 17 terrestrial would ensure the existence of liquid water.
Researchers have calculated that the planet TG b has a 60% probability of a temperature of 0 ° C to 50 ° C. TG c is cooler, but even there (if, of course, there is water) there is a chance to remain in a liquid state.
The authors call the “sweet couple” some of the most Earth-like exoplanets that have ever been discovered.
Note that red dwarfs, like the Tigarden star, make up about 75% of the stars in the Galaxy, so astronomers are very concerned about the question of whether life is possible under their dim light. Pessimists point to the fact that flashes often occur on such luminaries that can kill all living things . Optimists claim that this is not a sentence.
This article is written and prepared by our foreign editors writing for OBSERVATORY NEWS from different countries around the world – material edited and published by OBSERVATORY staff in our newsroom.
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