Figure 10-12 RIVUXG How a Star’s Size Affects its Spectrum These are the spectra of two stars of the same spectral type (B8) and surface temperature much greater than the Sun (13,400 K) but different radii and luminosities: (a) the B8 supergiant Rigel (luminosity 58,000 L_⊙) in Orion, and (b) the B8 main-sequence star Algol (luminosity 100 L_⊙) in Perseus.