1. The Great Orion Nebula Star Formation Region
Astrophotography
Hubble
Astrophotography
Chandra X-Ray
Hubble

2. b. Part II:
i. Stellar Evolution

3. The Hertzsprung-Russell (H-R) Diagram
RIGEL

4. b. Part II:
ii. Spectral Classification of Stars
Procyon – F5

5. Spectroscopy & Stellar Classification
Spectral Image
& Spectral Plot
Hydrogen
Balmer Lines
Spectral Image,
Spectral Plot &
Balmer Lines
He, Ca, H Lines

6. Summary of the Classification of Stars
Spectral
Class
Temperature (oK)
Strength of Balmer lines
Other lines to look for O
30, ,000
weak or not visible
Ionized He (4540Å) B
10, ,000
moderate A
7, ,000
strong F
6, ,500
weak
Ionized Ca (3930Å, 3970Å) strong compared to neutral H (4340Å) G
5, ,000 K
3, ,000
Many lines, neutral Ca 4230 Å M
< 3,500
not visible
Many lines

7. iii. Observations across the Electromagnetic Spectrum
b. Part II:
iii. Observations across the Electromagnetic Spectrum
Radio IR
Optical
X-ray
Composite
Cas A
Crab Nebula
Orion Nebula

9. b. Part II:
iv. Stellar Temperature, Radius, and Luminosity
v. Magnitude & Luminosity Scales………

10. b. Part II
The Distance Modulus: M = m - 5log10 (r) 10
Inverse Square Law: L = 1/r2
v. …….Distance Modulus & Inverse Square Law

12. Blackbody Radiation:
Planck’s Law & Wien’s Law
λmax = 2.9 x 107 /T

13. X Resources apod.nasa.gov http://soinc.org chandra.harvard.edu
aavso.org X