Homework NINE

Due Monday, April 14, 2003, at beginning of class.

Late penalty: 5 points if turned in by 5 p.m. on 4/15. Not accepted
after 5 p.m. on 4/16.

Answer Key

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.

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?

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?

What important events or developments occurred that led to the increased
level of oxygen in Earth's atmosphere?

Assuming that atmospheric gases will begin to escape from a planet's atmosphere
if the average gas velocity is onesixth the escape velocity of the planet,
at what temperature might ^{14}N 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 ^{14}N be able to escape?