Target Selection for SETI. I. A Catalog of Nearby Habitable Stellar Systems

Abstract

In preparation for the advent of the Allen Telescope Array, the SETI Institute has the need to greatly expand its former list of ~2000 targets compiled for Project Phoenix, a search for extraterrestrial technological signals. In this paper we present a catalog of stellar systems that are potentially habitable to complex life forms (including intelligent life), which comprises the largest portion of the new SETI target list. The Catalog of Nearby Habitable Systems (HabCat) was created from the Hipparcos Catalogue by examining the information on distances, stellar variability, multiplicity, kinematics, and spectral classification for the 118,218 stars contained therein. We also make use of information from several other catalogs containing data for Hipparcos stars on X-ray luminosity, Ca II H and K activity, rotation, spectral types, kinematics, metallicity, and Stromgren photometry. Combined with theoretical studies on habitable zones, evolutionary tracks, and third-body orbital stability, these data are used to remove unsuitable stars from HabCat, leaving a residue of stars that, to the best of our current knowledge, are potentially habitable hosts for complex life. While this catalog will no doubt need to be modified as we learn more about individual objects, the present analysis results in 17,129 Hipparcos habstars near the Sun (75% within 140 pc), ~2200 of which are known or suspected to be members of binary or triple star systems.