Number of transiting systems receiving Earth’s insolation, as a function of distance and mean number of habitable planets per star (η _⊕ ). The dotted curves are based on the RECONS (Research Consortium on Nearby Stars) list. The solid curves results from rejecting stars separated from a companion by less then 5″, as well as well as GJ 581 (already surveyed for transits) and GL 876 (eccentric planet in the habitable zone). The gray profiles are a d³ fit (± σ) to the list with close binaries removed.