Astr 101 – Fall 2013 – Homework Assignment #4
The Sun and General Properties of Stars

Provide a full answer to each of the following questions, using full English sentences. Answers should be no more than 4 lines long, and they must all fit in one page. Include a header with your name, the course number, and the assignment number at the top of the page. Make sure the page has smooth edges.

(1) Why is the Sun's core much hotter than its surface?

(2) In magnified pictures of the Sun, the surface appears covered with "granules". What are they?

(3) For which stars can we use the parallax method to find their distance, and why doesn't this work with all stars?

(4) Is it easier to find out how fast a star is moving towards/away from us, or sideways? What would you have to do to find out how fast a star moves in each of those two directions?

(5) If you want to find out how big a star is, why can't you just look at the size of that star in a picture taken with a very good telescope?