Summary: Extraterrestrial Life: Homework #5
Due, in class, Thursday April 10th
1) Briefly explain the radial velocity (or Doppler) method for detecting
extrasolar planets. Why does this technique work best for finding massive
planets, and those in short period orbits around their host stars?
The method is described in lecture #19. It works best for massive planets,
and for those in short period orbits, because the amplitude of the radial
velocity signal a planet induces on the host star is proportional to the mass
of the planet (so more massive planets yield a larger, easier to detect
signal), and inversely proportional to the square root of the orbital radius.
So short period planets in close orbits also yield stronger signals.
2) What is meant by the term "hot Jupiters"? Why is the existence of these
planets surprising in the context of the theory of planet formation that was
developed to explain the properties of the Solar System?
This is described in lecture #20.
3) The planet Saturn has a mass of 5.7 x 1026
kg and orbits the Sun at a
distance of 1.4 x 1012
m. If Saturn were the only planet in the Solar System,
calculate the velocity with which the Sun would move around the center