| 释义 |
UBV system UBV system[¦yü‚bē¦vē ‚sis·təm] (astronomy) A system of stellar magnitudes in which an object's apparent magnitude is measured at three wavelengths, labeled U, at 360 nanometers; B, at 420 nanometers; and V, at 540 nanometers; and is characterized by the color indices B-V and U-B, which are both defined to be 0 for a star of spectral type A0. Also known as Johnson-Morgan system. |