NCC - 86105

Spectral Classification

Created by Captain Benjamin Byrne on Sat Sep 1st, 2012 @ 8:26pm

Spectral Classification

Spectral classification is the classification of stars based upon the temperature of the photosphere. Each spectral class is further divided into 10 subclasses, ranging from 0 (hottest) to 9 (coolest). Stars are also placed into one of six categories based upon luminosity: 1a (luminous supergiants), 1b (less luminous supergiants), II (luminous giants), III (normal giants), IV (subgiants), and V (main sequence and dwarf stars).

For example, Sol is classified as type G2V. This indicates that is a Spectral Class G star of considerable temperature, and that it is a part of the main sequence.
Spectral Class O
COLOUR: Dark blue/violet
SURFACE TEMP: 28,000° - 50,000° K
COMPOSITION: Ionized atoms, helium
MASS: 60 Sols
RADIUS: 15 Sols
LUMINOSITY: 1,400,000
MAGNITUDE: -3
ABUNDANCE: 0.0000002135% of all stars
LIFETIME: 10 million years
EXAMPLES: Mintaka, Kalidar



Spectral Class B



COLOUR: Blue
SURFACE TEMP: 10,000° - 28,000° K
COMPOSITION: Neutral helium, some hydrogen
MASS: 18 Sols
RADIUS: 7 Sols
LUMINOSITY: 20,000
MAGNITUDE: -6
ABUNDANCE: 0.13% of stars
LIFETIME: 100 million years
EXAMPLES: Rigel, Alpha Eridani
Spectral Class A
COLOUR: Light blue
SURFACE TEMP: 7,500° - 10,000° K
COMPOSITION: Strong hydrogen and ionized metals
MASS: 3.2 Sols
RADIUS: 2.5 Sols
LUMINOSITY: 80.0
MAGNITUDE: +1
ABUNDANCE: 0.63% of stars
LIFETIME: 1 billion years
EXAMPLES: Vega, Sirius



Spectral Class F



COLOUR: White
SURFACE TEMP: 6,000° - 7,500° K
COMPOSITION: Hydrogen and ionized metals, calcium and iron
MASS: 1.7 Sols
RADIUS: 1.3 Sols
LUMINOSITY: 6.0
MAGNITUDE: +3
ABUNDANCE: 3.1% of stars
LIFETIME: 3 billion years
EXAMPLES: Canopus, Procyon
Spectral Class G
COLOUR: Yellow
SURFACE TEMP: 5,000° - 6,000° K
COMPOSITION: Ionized calcium, neutral and ionized metals
MASS: 1.1 Sols
RADIUS: 1.1 Sols
LUMINOSITY: 1.2
MAGNITUDE: +5
ABUNDANCE: 8% of stars
LIFETIME: 10 billion years
EXAMPLES: Sol, Ka`Tula, Capella



Spectral Class K



COLOUR: Orange
SURFACE TEMP: 3,500° - 5,000° K
COMPOSITION: Neutral metals
MASS: 0.8 Sols
RADIUS: 0.7 Sols
LUMINOSITY: 0.4
MAGNITUDE: +10
ABUNDANCE: 13% of stars
LIFETIME: 50 billion years
EXAMPLES: Arcturus, Aldebaran, Alpha Centauri
Spectral Class M
COLOUR: Red
SURFACE TEMP: 2,500° - 3,500° K
COMPOSITION: Ionized atoms, helium
MASS: 0.2 Sols
RADIUS: 0.3 Sols
LUMINOSITY: 0.04
MAGNITUDE: +15
ABUNDANCE: 78% of stars
LIFETIME: 200 billion years
EXAMPLES: Betelgeuse, Proxima Centauri, Wolf 359





Data and images from www.sttff.net


Categories: Stellar Cartography