An Etymological Dictionary of Astronomy and Astrophysics

In the Johnson → UBV system,
a reddening-free parameter which is related to the → effective temperature of stars and thus
provides a useful, but rough, discriminant for → spectral types.
It is expressed as: Q = (U - B) - 0.72 (B - V).

See also: → index.

In the Johnson → UBV system,
a reddening-free parameter which is related to the → effective temperature of stars and thus
provides a useful, but rough, discriminant for → spectral types.
It is expressed as: Q = (U - B) - 0.72 (B - V).

See also: → index.