Homework 5, Astr 305V, due: November 6

1a. How is the habitable zone defined? Explain what it refers to. Why is it defined in this way, you think?

1b. Why is it difficult to define accurately how large the actual habitable zone in the solar system is?

1c. For a star that has less mass than the Sun, what changes happen to location of the habitable zone, and what does that imply about the length of the orbital periods of planets (so, the length of their "year") that might be present in the habitable zone?

2a. Why is still technically challenging to be able to detect planets with the properties of Earth orbiting stars like the Sun? (Think of two particular techniques we discussed in class to detect planets, the Doppler or velocity method, and the transit method. It is hard for both cases. Explain for both cases why it is hard.

2b. Thinking about the masses of stars, is it easier to detect planets that orbit around stars with less mass than the Sun or around stars with more mass than the Sun? Explain your answer.