http://arxiv.org/abs/1006.2799

 

"On 15 June 2010 the Kepler Mission released data on all but 400 of the ~156,000 planetary target stars to the public. At the time of this publication, 706 targets from this first data set have viable exoplanet candidates with sizes as small as that of the Earth to larger than that of Jupiter. Here we give the identity and characteristics of 306 of the 706 targets. The released targets include 5 candidate multi-planet systems. Data for the remaining 400 targets with planetary candidates will be released in February 2011."

 

In the past exoplanets have been detected by watching the to-and-fro wobble of stars.

 

Kepler spacecraft detects planets by their cutting out a bit of the stars light as they pass in front. Using a large CCD retina it can watch a lot of stars at once. It doesn't have to do the delicate Doppler shift analysis to sense the star's motion. It can only "see" planets which pass in front of their stars. But it is a good cheap mass way to get a census of exoplanets. Once detected by Kepler, some will be studied by other (e.g. spectroscopic) methods.

 

http://kepler.nasa.gov/

Edited June 16, 201015 yr by Martin

Thanks for the update Martin. Kepler is a great idea. From what I gathered on Wiki whatever Earth-like planets around stars of interest we find, the actual number of such planets is probably about 215 times what they discover.

 

"For an Earth-like planet at 1 AU transiting a Sol-like star the probability is 0.465%, or about 1 in 215. At 0.72 AU (the orbital distance of Venus) the probability is slightly larger, at 0.65%; such planets could be Earth-like if the host star is a late G-type star such as Tau Ceti.

 

"In addition, the 1-in-215 probability means that if 100% of stars observed had the same diameter as the Sun, and each had one Earth-like terrestrial planet in an orbit identical to that of the Earth, Kepler would find about 465..."

 

http://en.wikipedia.org/wiki/Kepler_mission