Study Guide for In-class Exam #3
The third in-class exam will be on Wednesday, 17 November. It will consist
of 25 multiple-choice questions (4 pts each, as usual), and you will fill in your
answers in an accompanying "bubble" form with a #2 pencil.
Remember to work SLOWLY and CAREFULLY on the exam - take your time - there are only 25 questions and you have
the full 50 minutes!
Hints for studying:
- Below is a list of the various topics we've touched on since the second exam.
You are responsible for knowing what they mean and the context in which they fit into this class.
- This is a *guide* only - simply answering these questions will not adequately prepare for the exam!
- Binary Stars
- Types of Binaries: (1) Visual, (2) Spectroscopic and (3) eclipsing
- Know how to detect each type of binary system (above)
- Know what a lightcurve is for an eclipsing binary
- Close binaries and Roche Lobes: overflowing systems
- Binary with a compact object: nova
- Binary with a compact object: Supernova Type 1a
- Binary with a compact object: X-ray binary (NS or BH)
- Binary of two compact objects:
Our Milky Way Galaxy
- The Interstellar Medium: different forms of hydrogen: atomic, molecular, ionized
- HII regions: how do you detect them?
- Atomic gas: how do you detect it?
- Molecular gas: how do you detect it?
- Dust - what are the various ways in which dust affects starlight?
- Reflection nebula
- Dark nebula
- Interstellar Reddening
- approximate sizes (across, to the Galactic Center)
- location of the Sun in the Galaxy
- Parts of the Galaxy and their stellar content: disk, bulge, halo
- can we see (with visible telescopes) across the Galaxy? why or why not?
- Galactic Center: supermassive black hole (how do we know), obscured by gas, dust along our line of sight
- rotation of our Galaxy: INNER: wheel-like; OUTER: planetary-like (THEORY), but FLAT (OBSERVED)
- Evidence for dark matter in our Galaxy
- Spiral Arms
- Formation of the Galaxy; age of halo clusters vs. age of bulge clusters
Types & Properties of Galaxies
- Types: spirals, ellipticals, irregulars, dwarfs
- Properties: stellar & gas content, size, shapes, rotation (know very roughly these properties - no numbers!)
- how do spirals & elliptical differ?
- What is the evidence that most galaxies have dark matter?
Collisions between galaxies
- Galaxies are more likely to collide than stars (why?!)
- Physical effects of galaxy collisions, mergers?
- What happens during a galaxy collision?
- How can we study galaxy collisions when they take 100s of millions of years to happen?
Quasars and active galaxies
- what are their properties
- what fuels quasars, active galaxies?
Cosmic Distances
- What tools are used to find distances in astronomy?
- Parallax
- Cepheid variables
- Type Ia SN
- How do we find distances to the nearest stars?
- How do we find distances to the nearest galaxies?
- How do we find distances to the most distant galaxies?
Hubble's Law
- is a relationship between recessional velocity and distance.
- How do we measure recessional velocity?
- What is Hubble's Constant?
- What does Hubble's Law imply about the universe?
- Know the method (not mathematics!) for using use Hubble's Law to find distance to a galaxy
Galaxy Clusters and Dark Matter
- Why do we think there is dark matter in galaxies? (rotation curves, gravitational lenses)
- What are the possible types of dark matter?
- Local Group
- Properties of Virgo and Coma Clusters
- Superclusters
- Structure of the Universe
- Gravitational Lenses - what are they and what can we learn from them?