Main Sequence on the Hertzsprung-Russell Diagram  About 90% of the known stars lie on the Main Sequence and have luminosities which approximately follow the mass-luminosity relationship. The Hertzsprung-Russell Diagram is a plot of luminosity vs temperature, except that the temperature is decreasing to the right on the horizontal axis. The luminosity is noted both in multiples of the Sun's luminosity and absolute magnitude. | Sun on main sequence | Spectral types |
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| Mass-Luminosity Relationship For main sequence stars, the luminosity increases with the mass with the approximate power law:  A more conservative approach used by a number of astronomy texts is to use a relationship with the power left as a range of values.  The determination of a power relationship can be done by doing a log-log plot of the luminosities and masses. The slope of such a plot gives the power. Below is such a plot of data included in Harwit and attributed to the Royal Astronomical Society.  The power of 3.95 obtained from the upper part of this data shows the approach, but the range of masses is rather small. The value of 3.5 is most commonly used, and will be used in an estimate of stellar lifetimes. | IndexReferenceHarwitCh 8 |
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Sun on Main Sequence  | Main sequence discussion | Evolution of Sun to main sequence | Anticipated future of the Sun |
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Evolution of the Sun to the Main Sequence  | Main sequence discussion | Sun on main sequence | Anticipated future of the Sun |
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Anticipated Future of the Sun  | Sun on main sequence | Sun as red giant | Sun as white dwarf |
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