| 释义 |
> as lemmasOort constant Oort constant n. (also Oort's constant) either of two constants occurring in a pair of equations relating the radial and tangential velocities of a star in the Galaxy to its distance from the sun.The two constants are denoted by A and B. A is a measure of the shear in the Galactic disc in the neighbourhood of the sun, and is about 15 km s−1 per kiloparsec; B measures the vorticity of the material of the disc in the solar neighbourhood, and is about −10 km s−1 per kiloparsec.< |