A blue supergiant is a hot, massive, luminous star that is in an advanced post-main sequence stage of evolution. The best known example is Rigel. See supergiant for more details.

 

PV Telescopii star

A PV Telescopii star is a blue supergiant pulsating variable of spectral type Bp with weak hydrogen lines and strong lines of helium and carbon, sometimes called strong helium stars. They pulsate with amplitudes of about 0.1 magnitude and with periods as short as 2 hours and as long as about a year. Only about a dozen examples are known and they have been relatively poorly studied.