EPS SCI 3 Lecture Notes - Lecture 15: Red Dwarf, Main Sequence, Gliese 581
7 Dec 2016
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Methods to detect extrasolar planets (there are a lot of extrasolar planets!: direct: take photos of them-direct imaging (but resolution and contrast requirements makes it difficult to do so) Challenge 1: must collect enough light to detect the planet in the glare of the star. In the visible, a sun-like star is a billion times as bright as the reflected light from a planet. Take high contrast image with large telescope, try to block the light from the central star. Challenge 2: must resolve the planet and star as two separate objects (best resolving power of a telescope is given by /d but atmospheric turbulence degrades performance (d= diameter of telescope) Use large telescope in space or large ground-based telescopes with adaptive optics to get high resolution. Hr 8799: four planets discovered around hr 8799, 129 light years away from earth.
