Spectra of an exolanet

Gravitational microlensing has only been used to find a very few extrasolar planets. This particular one, i dont remember its name but i remember its spectrum was found, was discovered the usual way with the star wobbling around. Then it turned out that the planet passed between us and the star each orbit. They could get the spectrum by subtracting the light from when the planet was behind the star from when they were side by side as seen from here.

They are going to use this technique on finding the presence of water on Gliese 581 C.

Remember... these are just an artists impression taken in by a dip of light in a star, inset its called gravitational micro lensing... thats how they're finding extra solar planets, or brown dwarfs