A definition for one subclass of these entities offered by Keenan is having at least one broad H-alpha emissions line.
A definition for one subclass of these entities offered by Keenan is having at least one broad H-alpha emissions line. That subclass is extremely unstable since many its members frequently approach the Eddington limit. One type of these entities, which includes Antares, must have greater than ten solar masses and evolve following the beginning of helium fusion. These entities occupy the top of the H-R diagram. These stars include Sirius and Betelgeuse. For 10 points, name these extremely large stars.
A definition for one subclass of these entities offered by Keenan is having at least one broad H-alpha emissions line.
{supergiant}s [prompt on stars before mention]