AST101H5 Lecture Notes - Lecture 29: Giant-Impact Hypothesis, Doppler Spectroscopy, Double Planet
Document Summary
Earth"s (cid:373)oo(cid:374) is usually large compared to earth: double planet theory rejected, capture theory rejected, giant impact theory works the best. Because a star is so much brighter and larger than its planets: Must block out the star"s light to see the (cid:373)u(cid:272)h fai(cid:374)ter pla(cid:374)et (cid:374)e(cid:454)t to the star: planets orbit around the star over time, planets move with the star through space. The most successful methods discover planets by observing the star they are orbiting. Two methods: observe the motion of the star to detect it has planets, observe the brightness change of the star to detect it has planets. A planet does not orbit around its star. Both the planet and its star both orbit the balance point between them. As the planet orbits one time, the star must also orbit one time. If there are several planets, the star and all the planets orbit the center of mass for the whole system.
