[00:00]	The Hertzsprung-Russell (H-R) Diagram
[00:01]	Stellar Properties
[13:25]	Icebergs
[13:44]	Stellar Properties (reprise)
[16:43]	Stellar Masses
[18:15]	Stellar Properties (reprise)
[18:58]	Stellar Radii
[23:43]	Reading the H-R Diagram
[24:12]	Size and the H-R Diagram
[25:10]	Reading the H-R Diagram (reprise)
[25:54]	Stellar Radii (reprise)

Learning Objectives

1. Understand the difference between apparent properties, which vary with distance, and intrinsic properties.

2. Become comfortable reading and plotting the H-R Diagram.
   1. Connect the x-axis to temperature, to color, and to stellar type.
   2. Connect the y-axis to luminosity and to mass.
   3. Visualize lines of constant radius, stretching from the upper left to the lower right.
   4. Chart the range of the Main Sequence, where stars shine for most of their lives.
   5. See why the giant phase stretches up and to the right, to higher luminosities and lower temperatures.
   6. See why the white dwarfs are located in the lower left corner, indicating fairly high temperatures and fairly low luminosities.

3. Connect the radial velocity (Doppler shift) of a star in orbit around a companion to the companion's mass.

4. Visualize how white dwarfs cool, and so shift to lower temperatures and lower luminosities over time.

5. Understand how telescope sensitivity means that we can detect the faintest stars only near to our solar system, while bright stars can be found out to far larger distances.

6. Connect the fundamental properties of luminosity, temperature, and radius for stars. Become comfortable manipulating them algebraically.