Astrobiologically interesting stars within 10 parsecs of the Sun

Author(s)

Porto de Mello‚ G. ; Fernandez del Peloso‚ E. ; Ghezzi‚ L.

• Document type: Journal article
• Source: ASTROBIOLOGY; v. 6, n. 2, p. 308-331, 2006.

Abstract

The existence of life based on carbon chemistry and water oceans relies upon planetary properties, chiefly climate stability, and stellar properties, such as mass, age, metallicity, and galactic orbits. The latter can be well constrained with present knowledge. We present a detailed, up-to-date compilation of the atmospheric parameters, chemical composition, multiplicity, and degree of chromospheric activity for the astrobiologically interesting solar-type stars within 10 parsecs of the Sun. We determined their state of evolution, masses, ages, and space velocities, and produced an optimized list of candidates that merit serious scientific consideration by the future space-based interferometry probes aimed at directly detecting Earth-sized extrasolar planets and seeking spectroscopic infrared biomarkers as evidence of photosynthetic life. The initially selected stars number 33 solar-type within the total population (excluding some incompleteness for late M-dwarfs) of 182 stars closer than 10 parsecs. A comprehensive and detailed data compilation for these objects is still lacking; a considerable amount of recent data has so far gone unexplored in this context. We present 13 objects as the nearest "biostars," after eliminating multiple stars, young, chromospherically active, hard x-ray-emitting stars, and low metallicity objects. Three of these "biostars"-Zeta Tucanae, Beta Canum Venaticorum, and 61 Virginis-closely reproduce most of the solar properties and are considered as premier targets. We show that approximately 7% of the nearby stars are optimally interesting targets for exobiology. (AU)

• FAPESP's process: 00/06769-4 - The Galaxy and Star Formation
• Grantee: Zulema Abraham
• Support Opportunities: Research Projects - Thematic Grants