.. A bit of an update on our previous threads about Kepler's discovery of 1235 planetary candidates, of which they estimated 54 were in the 'Habitable Zone'...
Habitable zones
Quote:
CfA astronomers Lisa Kaltenegger (now at the Max Planck Institute for Astronomy) and Dimitar Sasselov have explored in more detail the conditions necessary for a planet to lie in its habitable zone. They take into account more carefully five factors: the incident stellar flux and its spectral character, the planet's eccentricity (how its distance from the star differs during its orbit), the planet's reflectivity including the effects of partial cloud cover, the greenhouse gas concentration, and finally, some details of the planet's atmosphere.
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A more accurate estimate finds that only six of the Kepler exoplanetary candidates could be in a habitable zone, assuming that they have atmospheres. The results are another important step in refining the search for Earth-like planets (not just Earth-sized planets) around other stars.
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More stringently define this thing called 'Habitable Zone', and you get a smaller answer than the original announcements … curious !
Anyway, I think of the 1235 candidates, about 17 have now been 'confirmed' with a total of 573 extrasolar planets now having been 'identified'.
Cheers