How many single stars among solar-type stars?

Abstract

Finally, the question of the number of true single stars may be aborded. In our sample of nearby solar-type stars, we observe 44% of the primaries with at least one stellar companion. Corrected from detection biases and taking into account the very low mass secondaries down to 0.01 solar masses, this number rises to 71%. Consequently, less than 30% of the primaries may be real single stars.

However, concerning the stability of the hypothetic planetary orbits and in the context of the search for extraterrestrial life, the long period systems (say with P > 100 yrs) may be considered as two independent single systems. As they represent about half of the total of the binary systems, we may expect actually about two thirds of the solar-type stars which could accept stable planetary orbits.