barospection

Annotated HR Diagram

  1. Most Important in all of Astrophysics
  2. Spectroscopy is a Keystone of Astronomy
  3. HUGE Dynamic Range of Stellar Luminosities
  4. MEDIUM range of Stellar Radii
  5. SMALLER range of Stellar Masses
  6. TINY range of Stellar Temperatures
  7. Luminosity Classes - Stellar Radii - Isochrones
  8. HRD explorer Show effect of varying star mass, luminosity, temperature and star radius
  9. Stellar Evolution

  10. electronexcitation jumps

  11. What is regulating the surface temperature of a star? Gas pressure in the stellar atmosphere a.k.a Surface gravity, Density
  12. Somewhat similar to the water kettle in your kitchen!
  13. Why is the surface temperature of a star orders of magnitude cooler than the core temperature?

What can you get out of Star brightness (Photometry)?

  1. Apparent magnitude $m$
  2. Calculate Absolute from Apparent Magnitude
  3. Absolute Magnitude $M$

What can you get out of Spectra (Spectroscopy)?

  1. Stellar Type & Temperature & Color Index (B-V)
  2. Stellar Mass - Isochrones
  3. Stellar Radius - Isochrones
  4. Chemical Composition - absorption/emission features
  5. Stellar Rotation - Thickness of lines
  6. Stellar velocities - Doppler Blue/Red shifts in stellar lines
  7. Hubble Constant Cosmological Expansion - Doppler Red shifts in Galaxies bright extra galactic objects Quasars, AGN, WR stars

The Ultimate yellow brick road !!