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Review Guide for Exam #2

Exam #2 will be give on March 26th from 6:30pm until 9:30pm. you may use calculators, be sure to bring yours. Also, the exam will be open book and open notes.

The exam will consist of three parts:

• Definitions
• Explanations
• Calculations

Definitions

1. Planetary Accretion
2. Brown Dwarf
3. "Hot Jupiter"
4. Planetary Migration
5. Snow Line
6. Planetary Transit
7. Neutron Star
8. White Dwarf
9. Globular Cluster
10. Open Cluster
11. Proton, Electron, Neutron, & Neutrino
12. Atom, Nucleus, Orbitals
13. Atomic Number & Atomic Mass Number
14. Periodic Table of Elements
15. Isotope & Ion
16. Electromagnetic Radiation & Electromagnetic Spectrum
17. Wavelength & Frequency
18. White Light
19. Angstrom

Explanations

1. Explain why astronomers think that Jupiter was the first of the planets in our solar system to have formed, and why they believe it's not coincidence that it formed right at the Sun’s snow line. Also, explain how astronomers believed Jupiter obtained its extensive atmosphere.
2. Explain the velocity and transit methods by which astronomers are able to infer that planets exist around stars other than the Sun.
3. Explain the term "observational bias" and give one example (i.e. the "hot" Jupiter observations).
4. Explain how the imbalance of neutrons in the nucleus of an atom produces radioactivity (i.e. an unstable isotope). In your explanation discuss the cases where the nucleus has too few neutrons and the too many neutrons.
5. Explain the dual nature of EMR
6. Explain how the wavelength of thermal radiation is inversely proportional to the temperature of the solid, liquid, or high density gas (i.e. Wien’s Law).
7. Explain how EMR is produced.
8. Explain how thermal radiation can produce either a continuous spectrum or an emission line spectrum.
9. Explain the three temperature scales (Fahrenheit, Celsius, and Kelvin).

Calculations

1. Be able to do transit times calculations estimating when an object on the celestial sphere will rise and set.

• Look up the celestial coordinates of the object (R.A. & Declination)
• Use the data at the back of your text book to build a Transit Time table for the 21^st of the month that you want to make your observation.
• Determine the transit time of the object on the 21^st of the month that you want to make your observation.
• Correct the transit time for the date of your observation (i.e. 4m per day).
• Remember, you add the correction for dates prior to the 21^st and subtract for dates after the 21^st.
• Correct the transit time for the longitude at which you are making your observation (i.e., add 39m for Abilene, TX).
• Altitude = 90 ^o – latitude + declination = 57.5^o + Declination Abilene, TX

2. Be able to convert from one temperature scale to another (i.e., from ^oF to ^oC and K, from ^oC to ^oF and K from K to ^oC and ^oF).

• ^oC = 5/9 (^oF - 32)
• ^oF = 9/5 ^oC + 32
• K = ^oC + 273
• ^oC = K – 273

3. Be able to use Wien’s Law to calculate the photospheric temperature of the stars.

Lambda _max = 2.898 x 10^-7/T

4. Be able to calculate the volume and density of stars (e.g., the volume and density of the white dwarf Sirius B).

• Density = Mass/Volume
• Volume = 4/3 pi * R³

5. Be able to calculate the radius of an extrasolar planet knowing the mass and density.

Radius = (3 * Mass/4pi * Density)^^1/3

 

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