True star

In Solar Storms, trillions of red dwarfs are cataloged, along with a comparable number of brown dwarfs. Since none of these are actually visible to the unenhanced human eye from Earth, some in the 23rd century did not consider them to be proper stars. True stars, by this definition, are those capable of sustaining helium fusion.

This is more pertinent when one considers that a red dwarf is incapable of sustaining a stargate, but any larger star can.