Possible biotic distribution in our galaxy Original Research Article

Astrobiology searches for life in the universe in other places different from Earth. To make a successful search it is necessary to know in what place it could be carried out and then we need to develop a theory that gives us the location of habitable planets. In this work we propose a model of the distribution of life in the galaxy. We use the concept of galactic habitable zone proposed by Gonzalez et al. [Icarus 152 (2001) 185] to determine the internal and external limits of the galactic ecosphere. We also calculate the ecosphere around the different spectral types of stars using the extreme condition limits of bacteria on Earth and study the possibility of planets with life out of this ecosphere. We also propose a region external to the ecosphere that could have habitable planets and we name this region the cryo-ecosphere.