AST 115: Chapter 4
28 Cards in this Set
| Front | Back |
|---|---|
|
Approximately when did the universe begin and in what state did it start?
|
14 billion years ago
pure energy until it cooled and matter could form
|
|
When the universe began what were the only elements?
|
Hydrogen and Helium
|
|
How were elements heavier than Helium produced?
|
Supernova explosions, literally star dust
|
|
What begins the star formation process?
|
gravitational contractions
|
|
What is the term used to describe a central concentration of spinning nebula forming a star?
|
Protosun
|
|
What is the temperature at which hydrogen fuses?
|
10 million Kelvin
|
|
What does the term accretion mean?
|
the gradual clumping of smaller particles to make ever-larger ones
|
|
According to the Nice Model, the inner part of the disk could only have what matter?
|
Rocky and metallic, because it was too warm for gases and ices to exist
|
|
What is the boundary where beyond gases and icy particles could exist?
|
Snow or Frost line
|
|
What planet moved from its original orbit due to gravitational interplay?
|
Neptune
|
|
What planet is believed to have formed first?
|
Jupiter
|
|
What group of planets formed first? Terrestrial or Jovian?
|
Jovian
|
|
What is the original order of the Jovian planets?
|
Jupiter, Saturn, Neptune, Uranus
|
|
What was Jupiter's distance from the Sun and what is its current distance?
|
3 AU
5 AU
|
|
What are 2 possible explanations of the low-eccentricity orbits of the planetesimals?
|
Terrestrials were built up from "seeds" in nearly circular orbits
or
The collision process favored the survival of planetesimals in low-eccentricity orbits
|
|
Approximately when did the terrestrials form?
|
4.1-4.6 billion years ago
|
|
What is the period where the terrestrials were bombarded by stuff by the jovians gravity?
|
Late Heavy Bombardment
|
|
What region extends 30-50 AU from the Sun?
|
Kuiper belt
|
|
What region extends approximately 50,000 AU from the Sun?
|
Oort Cloud
|
|
Material in the Kuiper belt and Oort cloud can be classified as?
|
Trans-Neptunian objects
|
|
Inhabitants of the Kuiper belt are called?
|
Kuiper belt Objects
|
|
What classifies plutinos
|
2:3 resonance orbits; 2 orbits for ever 3 neptune makes around the sun
|
|
What classifies Plutoids?
|
any trans-neptuninian objects with sufficient gravity to make a spherical shape
|
|
Where does the snow line exist?
|
between Mars and Jupiter in the main asteroid belt
|
|
How much mass exists in the asteroid belt?
|
5% of the moon's mass
|
|
What classifies a small solar system body? (sssb)
|
smaller asteroids, comets, satellites, meteroids
|
|
What is the difficulty in discovering exoplanets?
|
angular separation between star and planet is very small and a star will far outshine any of its planets
|
|
What are the techniques for discovering exoplanets
|
doppler wobble
stellar transits
wavy proper motion of stars
gravitational microlensing
|
AST 115: Chapter 2