Chapter 13, Problem 51EAP

Planet Around 51 Pegasi. The star 51 Pegasi has about the same mass and luminosity as our Sun and is orbited by a planet with an orbital period of 4.23 days and mass estimated to be 0.6 times the mass of Jupiter.
Use Kepler’s third law to calculate the planet’s average distance (semimajor axis) from its star. (Hint: Because the mass of 51 Pegasi is about the same as the mass of our Sun, you can use Kepler’s third law in its original form,  $p^2=a^3$

1. [Section 3.3]. Be sure to convert the period into years before using this equation.)
2. Suppose the planet reflects 15% of the incoming sunlight. Using Mathematical Insight 10.1, calculate its “no greenhouse” average temperature. How does this temperature compare to that of Earth?
3. Repeat part b, but assume that the planet is covered in bright clouds that reflect 80% of the incoming sunlight.
4. Based on your answers to parts b and c, do you think it is likely that the conditions on this planet could be conducive to life? Explain.