Wiktionary
n. (context astronomy English) motion of a star toward or away from the earth.
WordNet
n. velocity along the line of sight toward or away from the observer
Wikipedia
The radial velocity of an object with respect to a given point is the rate of change of the distance between the object and the point. That is, the radial velocity is the component of the object's velocity that points in the direction of the radius connecting the object and the point. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from or approaches the Earth.
In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity, which is determined by spectroscopy. i.e. by measuring the frequencies of light received from the object. By contrast, astrometric radial velocity is determined by astrometric observations (for example, a secular change in the annual parallax).
Usage examples of "radial velocity".
Then, remembering Swensons experience, he measured the angle of declination and the radial velocity as well.
Then, remembering Swenson's experience, he measured the angle of declination and the radial velocity as well.
We are being drawn toward it, of course, since an orbit has not yet been established, but have enough radial velocity of our own to—.
It must have lost radial velocity to friction and static gradients, been drawn into a cometary orbit, held together for a while by internal potentials.
What with such a short period, I had the radial velocity curves for each star almost as soon as the discovery was made.