spectra. Other chemically peculiar B-types stars are the mercury-manganese stars with spectral types B7-B9. Finally, the aforementioned Be stars show a prominent emission spectrum of hydrogen. Planets B-type stars known to have planets include the main-sequence B-type HIP 78530 and Mu² Scorpii. See also Herbig Ae/Be star Stellar classification, Class B Star count References Star types