Exoplanets: Practice Problem Solutions

1. A planet that orbits a star other than the Sun.

2. Watch a star's brightness. When a planet crosses its face the star dims briefly; the size of the dip gives the planet's size, and the time between dips gives its orbital period.

3. depth = (Rp / R*) squared, so Rp / R* = the square root of 0.01 = 0.1.

4. By the Doppler wobble of the star (51 Pegasi b, Mayor and Queloz, 1995).

5. Planets between Earth and Neptune in size. Our solar system has none, but they seem to be the most common type elsewhere.

6. The range of distances from a star where a planet could have liquid water on its surface.

7. It also needs the right mass, atmosphere and magnetic field; Venus is near the inner edge of the Sun's zone and is a furnace.