Although our sun is the only star in our Solar System, about half of stars are in binary systems, with two central stars orbiting their center of mass. Astronomers have recently started to detect planets in binary systems, which suggests that binary systems could conceivably host planets with just as much diversity as single star systems. Could planets orbiting binary stars be good places to search for signs of life?

My co-authors and I explore this question in a paper entitled “Habitable zone boundaries for circumbinary planets” and published in Publications of the Astronomical Society of the Pacific. We calculate the liquid water habitable zone for a planet orbiting a binary pair, which depends upon the particular combination of stars in the system. Dimmer red dwarf stars emit more infrared radiation than brighter yellow dwarf stars like our sun, for example; varying this combination of star types in the system can have a noticeable effect on the planet’s climate. But in general, planets orbiting a binary pair of stars should be about as likely to have habitable conditions as a similar planet orbiting a single star.