Question 3: Exoplanets (20%)
A. You observe a planet in transit around a star. Amazingly, the distant star has the same radius as the Sun, and the planet is exactly the same size as Saturn (but without a ring system). What would be the fractional change in flux during the transit?
B. If the orbital speed of the Saturn-like planet is 12.5 kms-1, how long would the transit last?
C. I want to observe the planet directly. From the Earth, the maximum distance of the planet from the star is 0.02". How big would a telescope's primary mirror (assume perfect adaptive optics) need to be in order to resolve them at a wavelength of 500nm, 1.2