Posted by
Hemos
on from the it's-like-the-earth-baby dept.
jrb writes "For the first time, a small planet (i.e. non-gas giant sized) has potentially been found outside the solar system, helped by a gravitational lensing effect that magnified it. The BBC is carrying the full story. "
Having been lucky enough to do a literature review on this topic recently (as part of my 3rd year u/g course) I can clear up a couple of issues;
The method used works as follows; when gravitational field of the planet warps the space around it, any light from the star that might otherwise have 'missed' the telescope/eye/pinhole camera (!) would be 'bent' back to the aforementioned instrument.
Hence we do _not_ see the planet, rather the effect of the planet on a star which is how all extrasolar planet detection methods (except one which has failed to date) work.
We have no instruments capable of resolving a planet, but NASA & ESA both havbe projects that in 2020-2060 will be able to do so at IR frequencies. Hence the BBC picture is wrong. All it pointed out was the star.
This method is not repeatable, since it relies on a chance that a background star acts as the source and the planet in orbit around an unseen star all line up for us.
You might think, 'doesn't the planet star lens the background one?' - it does! The additional blip caused by the planet on the light curve is what gives it away.
The typical distance to the background star (usually in the galactic plane) is 100 parsecs, the planet's parent star is usually half this distance for geometric reasons.
Hence it's really far away! We can tell virtually nothing about the planet apart from it's mass (which won't help diffrentiate between tiny gas giants and big terrestrial types).
If anyone want's more info (or even <gasp> a copy of my lit review, written for an intelligent person) then email me. Dosvidania tovarish!
-- --
Thus conscience does make cowards of us all - Hamlet
Slashdot Mirror
The method used works as follows; when gravitational field of the planet warps the space around it, any light from the star that might otherwise have 'missed' the telescope/eye/pinhole camera (!) would be 'bent' back to the aforementioned instrument.
Hence we do _not_ see the planet, rather the effect of the planet on a star which is how all extrasolar planet detection methods (except one which has failed to date) work.
We have no instruments capable of resolving a planet, but NASA & ESA both havbe projects that in 2020-2060 will be able to do so at IR frequencies. Hence the BBC picture is wrong. All it pointed out was the star.
This method is not repeatable, since it relies on a chance that a background star acts as the source and the planet in orbit around an unseen star all line up for us.
You might think, 'doesn't the planet star lens the background one?' - it does! The additional blip caused by the planet on the light curve is what gives it away.
The typical distance to the background star (usually in the galactic plane) is 100 parsecs, the planet's parent star is usually half this distance for geometric reasons.
Hence it's really far away! We can tell virtually nothing about the planet apart from it's mass (which won't help diffrentiate between tiny gas giants and big terrestrial types).
If anyone want's more info (or even <gasp> a copy of my lit review, written for an intelligent person) then email me. Dosvidania tovarish!
-- Thus conscience does make cowards of us all - Hamlet