Due: in class on February 7, 2008
Since 1995 over 200 extra-Solar planets have been discovered in over 100 other planetary systems (see the California & Carnegie Planet Search homepage). Here, we will investigate what these results are telling us about our Solar System and about how it may have formed. Go to the Marcy group's page http://exoplanets.org/planets.shtml where you will a list of the known planets, the star around which they orbit, their masses in terms of Jupiter's mass (Mjup), their sidereal revolution periods measured in days (Per (d)), the sizes of their orbits (semi-major axis, a) in terms of the Astronomical Unit (AU), and the orbital eccentricity (e).
1. How many Terrestrial-like (Earth-like) planets are in the list? ________ How many Jupiter-like planets are in the list? ________ What criterion did you use to decide whether a planet was Terrestrial-like or Jupiter-like in nature? _____________________________________________________________
2. What is the average eccentricity for all of the planets in the sample? ________ How does this compare to the average eccentricity for the planets in our Solar System? ______________________________________________________
3. What do we know about the sizes of the orbits of the Terrestrial
and Jupiter-like planets in our Solar System? __________________________________________________
Plot the planets on a graph where the vertical axis is the orbit size
and the horizontal axis is the mass of the planet.
Based on our Solar System, does the
plot look as you expected it to look? _____
4. How does the current observational situation concerning the properties of extra-Solar planetary systems affect our understanding of the formation of our Solar System? Do our theories need to be completely revised or are there other explanations?