Red Dwarf. It is a small and relatively cold star of the main sequence, either late K or M spectral type. This type forms the majority of stars, with mass and diameter values less than one third of those of the Sun (less than 0.08 solar masses are called brown dwarfs) and a surface temperature of less than 3,500 K.
Red dwarfs are stars of very low mass, less than 40% of the mass of the Sun, with a relatively low internal temperature and energy generated at a slow rate by the nuclear fusion of hydrogen into helium through the proton-proton chain. As a result, these stars emit little light, with a luminosity that in some cases barely reaches 1/10,000 of the solar luminosity. Even the largest red dwarf has only 10% of the Sun's luminosity.
It is located 20.5 light-years away, in the constellation Libra, and has a mass one third that of the Sun. Such red dwarfs are at least 50 times weaker than the Sun, and constitute the most common stars in our Galaxy: among the 100 stars closest to us, 80 belong to this class. Being so numerous in our neighbourhood, it is therefore essential to know whether such stars also harbour planets. Previous studies were rather unsuccessful: observations of some 200 red dwarfs revealed only two of them with planets.