Red Dwarf

A main sequence red dwarf is a star with less than half the mass of the Sun. The internal temperature initiates fusion but the reaction proceeds more slowly, at lower temperatures, than it does in the Sun. A red dwarf is on the lower right hand end of the main sequence line and is very long lived. They have low luminosity and consequently are not visible unless relatively close. There are estimated to be about ten times as many red dwarfs (M-type stars) in the galaxy as there are G-type stars like the Sun. Smaller rocky planets orbiting long lived M-type stars could be good candidates for Earth-type life systems, but they may be excluded because a planet that is warm enough, may be locked by tidal friction to rotate at the orbital period.

Note: nuclear reaction rates are not independent of chemical environment or temperature (as stated in many texts). There are known decay rates that are changed by ~1% when the atoms are combined in compounds. Nuclear reaction rates do not double with every 10°C rise in temperature like chemical reactions but doubling the internal temperature of a star increases the nuclear reaction rates by many orders of magnitude.

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