A B-type subdwarf (sdB) is a kind of subdwarf star with spectral type B. They differ from the typical subdwarf by being much hotter and brighter.[2] They are situated at the "extreme horizontal branch" of the Hertzsprung–Russell diagram. Masses of these stars are around 0.5 solar masses, and they contain only about 1% hydrogen, with the rest being helium. Their radius is from 0.15 to 0.25 solar radii, and their surface temperature is from 20,000 to 40,000 K (19,700 to 39,700 °C; 35,500 to 71,500 °F).
Heber
was invoked but never defined (see the help page).