ASTRON 1101 Lecture Notes - Lecture 11: Orbital Speed, Exoplanet, Orbital Period
20 Sep 2016
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Document Summary
Unit about 25 years ago, the only planets we knew about were those in the solar system. An astronomer orbiting proxima centauri wants to find planets orbiting the sun (4. 24 light years away) Jupiter has the best chance of being seen (it is the biggest, and reflects the most light) Seen from proxima centauri, the sun and jupiter are at most 4 arcseconds apart. However, jupiter is 1 billion times fainter than the sun: it"s lost in the glare. About 40 exoplanets have been found by direct imaging. This method favors finding large planets from their parent star. Indirect doppler technique: planets can be detected by the doppler shift they produce in their parent star. Jupiter and the sun each orbit the center of mass the sun-jupiter system. Mass of sun = 1000x the mass of jupiter. Sun"s orbit = 0. 001x the size of jupiter"s orbit.
