title: The galactic habitable zone and the age distribution of complex life in the Milky Way.
abstract: We modeled the evolution of the Milky Way Galaxy to trace the distribution in space and time of four prerequisites for complex life: the presence of a host star, enough heavy elements to form terrestrial planets, sufficient time for biological evolution, and an environment free of life-extinguishing supernovae. We identified the Galactic habitable zone (GHZ) as an annular region between 7 and 9 kiloparsecs from the Galactic center that widens with time and is composed of stars that formed between 8 and 4 billion years ago. This GHZ yields an age distribution for the complex life that may inhabit our Galaxy. We found that 75% of the stars in the GHZ are older than the Sun.
authors.affiliation: Department of Astrophysics, University of New South Wales (NSW), Sydney, NSW 2052, Australia. charley@bat.phys.unsw.edu.au
authors.forename: Charles H
authors.initials: CH
authors.lastname: Lineweaver
authors.forename: Yeshe
authors.initials: Y
authors.lastname: Fenner
authors.forename: Brad K
authors.initials: BK
authors.lastname: Gibson
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D003198:Computer Simulation; D019418:Evolution, Chemical; D019419:Evolution, Planetary; D018559:Exobiology; D005118:Extraterrestrial Environment; D008962:Models, Theoretical; D011336:Probability; D013995:Time