Main+Sequence+Stars+2B

MAIN SEQUENCE STARS: these are about 90% of the stars on the HR Diagram. they follow along a band that runs from the upper left corner to the lower right corner of the diagram. hottest=brightest coolest=dimmest. brightness is related to the mass of the stars. some of the hottest stars are up to 50 times more massive than the sun! but some are only 1/10 as massive, too. the main sequence stars appear in decreasing order on the HR diagram. (info and defination from text book)


 * Where does the Main Sequence Star (also known as dwarf stars) come from?** After a few million years, a protostar starts burning hydrogen into its core, passes through the T-Tauri stage, and than becomes a main sequence star.

The Main Sequence Star's total mass is determined by all of its structeral properties.

There are 3 divisions in a stellar interior: the nuclear burning core, convective sone, and radiative zone. The nuclear burning core generates energy. Then, energy is transferred toward the surface either radiatively or convectivly, depending on which is more efficent based on temperatues, densities, opacities. The properties of a main sequence star can be understood by considering the various physical processes acting in the interior. First is the hydrostatic balance, also called hydrostatic equilibrium. This determines the density structure of the star as the internal pressure balances against the force of gravity.

The main sequence is where the majority of the stars is located. Stars spend most of their life in the main sequence stage. Main Sequence stars are called Main Sequence stats because they burn Hydrogen in their cores. Main sequence stars include red giants and supergiants.

The SUN will spend 10 billion years in the main sequence stage!