Most stars that look at the naked eye have a member, that is, they appear in pairs. Sometimes there are more than two stars in the group that rotate each other. In particular, 80% of the big stars are paired, so astronomers thought it was the most common. Now, however, they have focused on small stars and have seen that the minority has a partner. In fact, three-quarters of the red dwarfs of the Milky Way have no friends, they only appear.