B-type main-sequence star

All of the spectral classes, including the B type, were subdivided with a numerical suffix that indicated the degree to which they approached the next classification.

They have a higher mass loss rate than smaller stars such as the Sun, and their stellar wind has velocities of about 3,000 km/s.

Because the CNO cycle is very temperature sensitive, the energy generation is heavily concentrated at the center of the star, which results in a convection zone about the core.

Be stars are generally thought to feature unusually strong stellar winds, high surface temperatures, and significant attrition of stellar mass as the objects rotate at a curiously rapid rate, all of this in contrast to many other main-sequence star types.

In other words, these particular stars' emissions appear to undergo processes not normally allowed under 1st-order perturbation theory in quantum mechanics.

Some of the B-type stars of stellar class B0–B3 exhibit unusually strong lines of non-ionized helium.

In contrast, there are also helium-weak B-type stars with understrength helium lines and strong hydrogen spectra.