1. Spectral Star Analysis
Astrophysics
Spectral Star Analysis

2. Diagram Placements Spectral Analysis ? How do we place them?
The process of determining stellar types from observed spectral absorption lines.

3. Obtaining a Stellar Spectrum

4. Spectral Key

5. Spectral Key

6. Spectral Types “Oh, Be A Fine Guy/Girl, Kiss Me”
O B A F G K M
Each class is subdivided 0-9
i.e. B0, B1, … B9, A0, …
Then further sub divided by Roman Numerals
(I – V)
And additionally divided alphabetically
(a, b, c, d, etc…)

7. Spectral Types Temperature Variations Color Variations
O: hottest, M: coolest
Color Variations
O, B: Blue
A, F, G: Yellow/Orange
K, M: Red

8. Spectral Types O >16 B 2.1 – 16 A 1.4 – 2.1 F 1.04 – 1.4 G
Spectral Class
Mass (in multiples of the Sun’s mass) O
>16 B
2.1 – 16 A
1.4 – 2.1 F
1.04 – 1.4 G
0.8 – 1.04 K
0.45 – 0.8 M
0.08 – 0.45

16. d Leo
b Leo
15_Monocerous

17. s Leo
HD-27808
Rho Auriga

18. Wein’s Law

21. Temperature from Wavelength
Wien’s Law
lmax*T = cm K