Difference between revisions of "Planetary and Stellar classes"
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In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure of the temperature in this chromosphere. Unlike what is the case for planets, stellar bodies are often classed on two scales - size and temperature/color. | In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure of the temperature in this chromosphere. Unlike what is the case for planets, stellar bodies are often classed on two scales - size and temperature/color. | ||
| + | ==Stars based on color and temperature== | ||
| + | The following table ''does'' include a rough gauge of mass, but this has little to do with the size. | ||
| + | {| border="1" | ||
| + | |- bgcolor="#800000" | ||
| + | !Class!!Surface Temperature!!Color!!Mass (Solar Masses)!!Fraction of All Main Sequence Stars | ||
| + | |- | ||
| + | |'''O'''||≥ 33,000 K||Blue||≥ 16 M||~0.00003% | ||
| + | |- | ||
| + | |'''B'''||10,000–33,000 K||Blue/Blue-White||2.1 - 16 M||0.13% | ||
| + | |- | ||
| + | |'''A'''||7,500–10,000 K||White||1.4 - 2.1 M||0.6% | ||
| + | |- bgcolor="#404040" | ||
| + | |'''F'''||6,000–7,500 K||Yellowish White||1.04 - 1.4 M||3% | ||
| + | |- | ||
| + | |'''G'''||5,200–6,000 K||Yellow||0.8 - 1.04 M||7.6% | ||
| + | |- bgcolor="#404040" | ||
| + | |'''K'''||3,700–5,200 K||Orange||0.45–0.8 M||12.1% | ||
| + | |- bgcolor="#404040" | ||
| + | |'''M'''||≤ 3,700 K||Red||≤ 0.45 M||76.45% | ||
| + | |} | ||
Revision as of 15:45, 11 March 2012
The following information is gathered from various sources, including NASA documents, The original FASA Star Trek RPG, Memory Alpha (where it does not flagrantly disagree with otherwise established classes), and various other sources.
List of known classes
| Class | Surface | Atmosphere | Description | Example |
|---|---|---|---|---|
| A | tenuous, may not be present | reducing; methane, etc. | radiates heat, "failed" star | Jupiter, Saturn |
| B | tenuous, may not be present | reducing | non-radiant | Neptune |
| C | iron/silicate | reducing/dense | high surface temperature | Venus |
| D | nickel-iron/silicate | (A-G)none, (H-N)tenuous | asteroids | Ceres |
| E | silicate, some metals | reducing/oxidizing | large molten core | Janus IV |
| F | silicate, some metals | oxidizing | very young | Delta Vega |
| G | silicate | oxidizing, thin | desert planet | Rigel XII |
| H | silicate | variable | geologically active | Gothos |
| I | metallic/silicate | fluid, very dense | small/young | Excalibis |
| J | silicate | very tenuous, noble gasses | moons | Luna |
| K | silicate | tenuous, some water | adaptable with pressure domes | Mars |
| L | silicate/water | oxidizing | geologically inactive | Psi 2000 |
| M | silicate/water | oxidizing | geologically active | Terra |
| N | water entirely | oxidizing | pelagic planet | Argo |
| P | water/silicate | oxidizing | glacial planet | Breen |
| R | water/silicate | negligible | Rogue | Dakala |
| S | small dense metallic | reducing | small ultra gas giant | Braxis |
| T | small dense nickel-iron | reducing | large ultra gas giant | Luava |
| Y | metallic/silicate | reducing | demon class | Silver Blood planet |
Stellar Classes
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure of the temperature in this chromosphere. Unlike what is the case for planets, stellar bodies are often classed on two scales - size and temperature/color.
Stars based on color and temperature
The following table does include a rough gauge of mass, but this has little to do with the size.
| Class | Surface Temperature | Color | Mass (Solar Masses) | Fraction of All Main Sequence Stars |
|---|---|---|---|---|
| O | ≥ 33,000 K | Blue | ≥ 16 M | ~0.00003% |
| B | 10,000–33,000 K | Blue/Blue-White | 2.1 - 16 M | 0.13% |
| A | 7,500–10,000 K | White | 1.4 - 2.1 M | 0.6% |
| F | 6,000–7,500 K | Yellowish White | 1.04 - 1.4 M | 3% |
| G | 5,200–6,000 K | Yellow | 0.8 - 1.04 M | 7.6% |
| K | 3,700–5,200 K | Orange | 0.45–0.8 M | 12.1% |
| M | ≤ 3,700 K | Red | ≤ 0.45 M | 76.45% |