[hal-01078051] Detectability of Earth-like planets in circumstellar habitable zones of binary star systems with sun-like components

Given the considerable percentage of stars that are members of binaries or stellar multiples in the solar neighborhood it is expected that many of these binaries host planets possibly even habitable ones The discovery of a terrestrial planet in the α Centauri system supports this notion Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems classical approaches to determining habitable zones HZ especially in close S-type binary systems can be rather inaccurate Recent progress in this field however allows us to identify regions around the star permitting permanent habitability While the discovery of α Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities it remains to be shown whether this is also the case for Earth analogs in HZs We provide analytical expressions for the maximum and rms values of radial velocity and astrometric signals as well as transit probabilities of terrestrial planets in such systems showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets' detection As an example we discuss the detectability of additional Earth-like planets in the averaged extended and permanent HZs around both stars of the α Centauri system



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