In article ,
writes:
I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc).

It's a very difficult observation; it took 459 separate observations
over 3.5 years on a big telescope with a very impressive modern
instrument. Plus extremely complex data reduction, removing many
effects much larger than the planet signal. The final velocity
signal is only half a meter per second! What surprises me is that
the planet was detected at all, not how long it's taken.

The scientific paper is at
http://www.nature.com/nature/journal...ture11572.html
but you'll need a subscription or to pay to read it. The press
release, which excellent, is at
http://www.eso.org/public/news/eso1241/

The press release has a link to what appears to be the scientific
paper minus Nature's editing and minus the Supplementary Information
at
http://www.eso.org/public/archives/r...1/eso1241a.pdf

Phil Plait's excellent blog, which shows the plot of the key data,
is at
http://blogs.discovermagazine.com/ba...-has-a-planet/

Nature's commentary on the discovery, also pay or subscription, is at
http://www.nature.com/nature/journal...ture11636.html
(I wouldn't pay for this, but it's worth reading if you have a
subscription. Among other things, it points out that because the
analysis is so tricky, the discovery needs to be confirmed by other
methods before being 100% accepted.)

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