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Scientists Find Solar System Like Ours
mlimber writes "The NYTimes has up a story about the discovery of a solar system that is analogous to ours. Of the 250 or so exoplanets found thus far, 'few of them are in systems that even faintly resemble our own. In many cases, giant Jupiter-like planets are whizzing around inside the orbit of Mercury,' whereas in this new system, 'a planet about two-thirds of the mass of Jupiter and another about 90 percent of the mass of Saturn are orbiting a reddish star about half the mass of the Sun, at about half the distances that Jupiter and Saturn circle our own Sun.' The researchers used gravitational microlensing to detect the planets, and two of the lead authors of the paper to be published in Science are amateur astronomers, one of whom describes herself as 'an ordinary New Zealand mother.'"
Being a graduate student at one of the universities involved, i did some modeling on this event (although we weren't quite up with the game, so our findings weren't used in the report).
The term 'lensing' is a bit of a misnomer, as that implies that you're looking at the source star; which is essentially a giant flashlight that allows us to probe the lens for information about it's planets.
The lens star acts to bend the light from the source, creating multiple and distorted images of it (which are too close together to resolve). Observing the sky from earth, these multiple images have the effect of increasing the net flux measured (in laymans terms, the star gets brighter).
When the lens star has planets (especially, as in this case, one close to what as known as the 'einstein ring') it causes large perturbations to the (otherwise fairly simple) lightcurve. With appropriate mathematical models and massive amounts of computing power, the parameters that give the best fitting theoretical lightcurve can be found.
Combining this with external information and a good dose of physical and statistical insight, it is possible to say to a reasonable degree of confidence (usually never 100%) that you have found such and such a system.
In reality, the astronomers who measure the data are only a very small part of the overall picture, but the media find a much better story in "amateur astronomer finds extrasolar planets" than "scientists use computer grid to minimize 10 dimensional chi^2 hypersurface" so they get all the attention.