Astronomy 201 

Homework NINE


  1. From the List of Known Exoplanets, pick one planet (click on the name of the star; you may not choose 51 Peg). From the light curve figure, you can obtain (or are given) the parameters you need to calculate the mass of the planet (also often given on the figure). Use the mathematics for exoplanet studies (see class notes) to derive (not just state) the mass of the planet.  For a plausible range of the inclination of the orbit, what are plausible upper and lower limits for the mass of this planet? Make estimates for the errors in how well known the period and radial velocity are known (these are given for some star/planet systems) and discuss the impact of these errors on the estimates for the mass of the planet.
  2. What hidden measurement biases likely affect the known distribution of planet masses (number of planets vs. mass of planet)? What conclusions can you draw about the likely real distribution of planet masses that should not be affected by known biases?
  3. Can you draw any firm or tentative conclusions yet (if so, what are they?) about how our solar system fits into the big picture of planetary systems?
  4. What important events or developments occurred that led to the increased level of oxygen in Earth's atmosphere?
  5. Assuming that atmospheric gases will begin to escape from a planet's atmosphere if the average gas velocity is one-sixth the escape velocity of the planet, at what temperature might 14N possibly be able to begin to escape from Mars?  If the surface temperature of Mars is about 220K and the maximum temperature of gas high in the atmosphere is 300 K warmer than the surface, would 14N be able to escape?