ASTRO-110 Lecture Notes - Lecture 21: Radial Velocity, Circumstellar Habitable Zone, Ellipse
9 Sep 2020
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Document Summary
Techniques used to detect extrasolar planets can be divided into two categories. Obtaining an image of the planet directly. Direct imaging of planets can be very difficult. Establishing the presence of a planet by the effect on the star. Almost all extrasolar planets have been found this way. Keplers laws (newton) will tell us that two bodies will orbit the center of their masses. Technically means that planets are not orbiting the sun, by the center of the solar system (the sun is too) Jupiter orbits the centre of the mass in 12 years, that means outr sun does too. Carefully measuring the small motions of stars due to gravitational tugs of planets allow us to determine. Saturn also exhibits a pull on sun, though less than jupiter. Thus the path of the sun becomes very complex. Implies trying to detect those wobbles due to gravitational tugs. Carefully measure the position of stars over time.
