A Life Bearing Exoplanet - The Next Great "Page-One" Discovery in Space
Of the three remaining page-one discoveries yet to be made in exoplanetary science, the first, identification of a potentially habitable Earth-mass planet around another star (most likely in the Proxima Centauri system) is due to happen any day if it hasn't already with the discovery of Gliese 581d in the Constellation Libra .
The timelines for remaining two discoveries -the detection of a life-bearing planet and contact with extraterrestrial intelligence- are pure conjecture.
The breakthrough detection of a habitable Earth will most likely come from the high-precision Doppler monitoring of a nearby red dwarf star, by the Geneva-based European Space Agency team or the prolific California & Carnegie and Anglo-Australian planet-search teams, who recently discovered 28 new planets outside our Solar System.
The team at oklo.org's Systemic Blog-"characterizing extrasolar planetary systems"- bets that the Swiss find a habitable Earth orbiting Proxima Centauri.
If you want to send an interstellar probe, you're going to chose the closest star system to the Sun: the Alpha Centauri system. Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star. The bright stars Alpha Centauri A and B form a close binary as they are separated by only 23 times the Earth- Sun distance - slightly greater than the distance between Uranus and the Sun.
Due to their proximity to the Star Sol, the stars of this system have been objects of intense interest among astronomers. Stars A and B have been selected as two of the top 100 target stars for NASA's Terrestrial Planet Finder (illustration above) to image small rocky planets in Earth-type habitable orbits. In addition, all three stars are among the "Tier 1" target stars for NASA's optical Space Interferometry Mission (SIM) to detect a planet as small as three Earth-masses within two AUs of its host star. Astronomers are also hoping to use the ESA's Darwin group of infrared interferometers to analyze the atmospheres of rocky planets found in the "habitable zone" around all three stars for evidence of Earth-type life.
The Oklo team has looked in great detail at the prospects for detecting a habitable planet around Alpha Centauri B, and are working to build a special-purpose telescope in South America to carry out this campaign. Proxima b, on the other hand, might be ready to announce right now on the basis of a HARPS data set, and the case is alarmingly compelling.
To quote the Systemic Oklo team: "Proxima is effortlessly old, adequately quiet, and metal-rich. If our understanding of planet formation is first-order correct, it has several significant terrestrial-mass planets."
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