The Catalogue of Astrobiologically Interesting Stars 
Within 15 Parsecs of the Sun

Gustavo F. Porto de Mello
Eduardo F. del Peloso, Luan Ghezzi
UFRJ/Observatório do Valongo

We present a detailed and up-to-date data compilation on state of the evolution, mass, age, atmospheric parameters, chemical composition, multiplicity, chromospheric activity and galactic orbits for the solar-type stars within 15 pc of the Sun. These objects are potentially interesting targets for space interferometry probes looking for telluric planets suitable to life based on carbon chemistry and water oceans. For the stars within 10 parsecs published data is essentially complete, but for those within 10 to 15 parsecs from the Sun spectroscopic determinations of [Fe/H] and Teff are only 71% complete; and data on chromospheric activity, 90% complete. For those stars with both a chromospheric age constraint and spectroscopically determined metallicities, we analyze their evolutionary status, determine their masses and ages and select a subsample of non-binary stars with adequate metallicity, mass, age older than 3 billion years and galactic orbit close to the solar position at the galactic co-rotation radius. The 3 billion year age limit is a recent estimate of the minimum time elapsed for planetary evolution to allow biospheres in telluric planets to develop high oxygen content: this phase marks the possibility of space-based interferometric detection of biological activity by the ozone/methane infrared signatures. We show that one third of the solar type stars in the vicinity are potential targets for astrobiology. We also find that some objects previously listed as astrobiologically interesting targets turn out to be a) young, chromospherically active stars, b) systems with giant planets in orbits potentially disruptive to planets in the continuously habitable zone; c) be subgiants too evolved to allow habitable planets to have survived their increased luminosity; d) have high eccentricity galactic orbits, far from the co-rotation radius, potentially exposing them to frequent supernova explosion irradiation events and encounters with giant molecular clouds. We also present a proposal for the use of the future SOAR Goodman & STELES spectrographs towards a complete survey of chromospheric activity and chemical composition of the solar-type stars in the solar neighborhood.