Stellar Classification Systems

Stellar Classification

SystemsFernandez, Jhan-Curt

• Secchi Classifi cati on System

• Harvard Classifi cati on System

• Yerkes Classifi cati on System

Secchi Classification System

Class I- White and Blue Stars

Class II- Yellow Stars

Class III- Orange to Red Stars

Class IV- Red Stars

Class V- Emission Line Stars (Wolf-Rayet, Be stars, etc.)

Harvard Classification System

O-Type: blue

B-Type: blue white

A-Type: white - blue white

Y-Type: brown

L-Type: red

K-Type: yellow orange

M-Type: orange red

F-Type: white T-Type: purple red

G-Type: yellowish white

Temperature

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Yerkes (MKK) Classification System

Class 0

Class I

Class II

Class III

Class V

Class VI

Class IV

Class VII

Temperature and Luminosity

• Class 0- Hypergiant Stars• Class I- Bright Supergiants

Class Ia0: hypergiants /extremely luminous supergiants

Class Ia: luminous supergiants

Class Iab: intermediate luminous supergiants

Class Ib: less luminous supergiants

• Class II- SupergiantsClass IIa: β Scuti-like stars

Class IIab: HR 8752 Cassiopeiae-like stars

Class IIb: HR 6902 Ophiuchi-like stars

• Class III- Normal Giants

Class IVa: ε Reticuli-like stars

Class IVab

Class IVb : HR 672A Ceti-like stars

• Class IV- Subgiants

Class IIIa: ρ Persei-like stars

Class IIIab: δ Reticuli-like stars

Class IIIb: Pollux-like stars

• Class V- Main Sequence Dwarf Stars

Class Vz: LH10:3102-like stars

Class Vb: 85 Pegasi A-like stars

Class VabClass Va: AD Leonis-like stars

• Class VI- Subdwarf Stars

esd (Extreme Subdwarf Stars)

sd (Subdwarf Stars)

• Class VII- White Dwarf Stars