Dr. Mary Lou West
Department of Mathematical Sciences
Montclair State University, Montclair, NJ
Textbook: "Intro to Modern Astrophysics" by B. Carroll and D. Ostlie, 2e, 2007
Comets' orbits are ellipses around the sun. Most comets come into the inner part of the solar system from far beyond Jupiter's distance. They are usually first sighted when they pass the orbit of Mars on the way toward perihelion. Suppose that we determined that a newly-seen comet was on a collision course with the Earth. How much time would we have to do something to avert a collision? How long would we have if the collison would take place after the comet passed perihelion?
There is a nice animation of a comet's orbit and tail properties at www.windows.ucar.edu/tour/link=/comets/comet_model_interactive.html.
Look up the parameters of 20 comets.
( neo.jpl.nasa.gov/cgi-bin/neo_elem?type=NEC
has a good starting list)
The three projects are
1.A) Comets with periods from 1 to 10 years
1.B) Comets with periods from 10 to 50 years
1.C) Comets with periods from 50 to 200 years
What is a (semi-major axis) in terms of perihelion and aphelion distances?
Use ORBIT to calculate the time from perihelion to Earth crossing, and to Mars crossing. See Appendix J (p A-17).
Discuss these two times for each of your comets.
What is the Torino scale and its levels?
Describe the Spacewatch Program, the Spaceguard program, and what humans plan to do if a collision is imminent.
Describe a close miss that actually happened.
The orbits of asteroids are also ellipses about the sun. Most of them stay in nearly circular orbits between the orbits of Mars and Jupiter, but some of them have elongated paths which bring them into the vicinity of the Earth. They are sometimes first sighted when they pass the orbit of Mars on the way toward perihelion. Suppose that we determined that a newly-seen asteroid was on a collision course with the Earth. How much time would we have to do something to avert a collision? How long would we have if the collison would take place after the asteroid passed perihelion? Note that asteroids are VERY hard to spot coming from sunward.
Look up the parameters for 20 NEOs.
( neo.jpl.nasa.gov/cgi-bin/neo_elem
has a good starting list)
The two projects are
2.A) Earth crossing asteroids with periods from 1 to 2 years
2.B) Earth crossing asteroids with periods from 2 to 5 years
What are the various classes of earth-crossing asteroids?
Use ORBIT to calculate the time from perihelion to Earth crossing, and to Mars crossing. See Appendix J (p A-17).
Discuss these two times for each of your asteroids.
What is the Torino scale and its levels?
Describe the Spacewatch Program, the Spaceguard program, and what humans plan to do if a collision is imminent.
Describe a close miss that actually happened.
What happenned on Venus?
The Vogt-Russell theorem asserts that a star's structure is uniquely determined by its mass and its chemical composition.
Look up the parameters for 20 real main sequence stars (sometimes called dwarfs, but not white dwarfs). A good starting place is James Kaler's star of the week site at
www.astro.uiuc.edu/~kaler/sow/class.html
The three projects are
4.A) Stars of spectral types O, B, and A, standard composition
4.B) Stars of spectral types F, K, and M, standard composition
4.C) Stars of spectral type G
Using StatStar calculate about 10 static stellar models for the main sequence stars you need. See Appendix L (p A-23), and stellar data for main sequence stars (Appendix G, p A-9). For projects 4.A and 4.B calculate models with standard composition (hydrogen = .70, metals = .008). However, for project 4.C calculate models with mass = 1 solar mass, composition varying from metals = .001 to .050. Look for data on a few Population II stars, metal-poor stars, or globular cluster stars to compare to the models.
Plot your models as well as the data for the real stars on a Hertzsprung-Russell diagram.
Discuss the trends you see, and also how well these models match the real stars.
Look up the properties and/or images of 3 colliding galaxy pairs. See Ch. 26 (p 999) and try an Internet image search for colliding galaxies or ring galaxies.
Use GALAXY (Appendix M, p A-26) to calculate 20 colliding galaxy scenarios.
Compare these with the 3 real examples.
The two projects are
5.A) Side-swipe collisions, see problem 26.18 (Whirlpool galaxy) for a start.
5.B) Head-on collisions, see problem 26.20 (Cartwheel galaxy) for a start.
Look up the properties of 3 black holes.
The two projects are
6.A) Stellar mass black holes (3 to 80 solar masses)
6.B) Supermassive black holes (thousands or millions of solar
masses)
Use ORBIT to calculate the orbit of a close companion object of various eccentricities.
Calculate the fastest speed of the object. (Which part of the orbit is this in?)
Modify ORBIT to use relativistic corrections. Compare the corrected version to the original output and to the real objects.
This page is http://www.csam.montclair.edu/~west/ast480/approjects.html