ASTRONOMY: ADAMS AND JOY 
239 
THE MOTIONS IN SPACE OF SOME STARS OF HIGH RADIAL 
VELOCITY 
By W. S. Adams and A. H. Joy 
Mount Wilson Observatory, Carnegie Institution of Washington 
Read before the Academy, April 28, 1919 
The motion in space of the stars of very high radial velocity is of exceptional 
interest because such stars are usually of comparatively low intrinsic bright- 
ness and probably of small mass as well. It might, therefore, be expected 
that these stars would show the effects of stream motion strongly and that the 
components of their velocities might be related to the fundamental plane of 
the stellar galaxy. 
As a basis for the study we selected all stars with radial velocities exceed- 
ing 80 km. per second for which proper motions and parallaxes are available. 
This gave a total of 37 stars with velocities ranging between 81 and 339 km., 
the latter the highest stellar radial velocity so far known. It is of interest to 
note that the largest velocities of approach and of recession are very nearly 
equal. The parallaxes of all but five of these stars have been derived by the 
spectroscopic method, the trigonometric values being used for the remainder. 
After elimination of the solar motion the velocity-components and the 
apices of the stars relative to the centroid of the stellar system were deter- 
mined by the aid of their proper motions, parallaxes and radial velocities. 
These components were in turn reduced to the plane of the galaxy and the 
galactic coordinates of the apices and the total velocities were calculated for 
all the stars. 
Some of the results of the investigation are shown graphically in the ac- 
companying figure. The plane is that of the galaxy with the apices shown 
in projection. Vectors drawn to the origin represent the direction and amount 
of motion in this plane. 
A few of the more important conclusions may be indicated briefly. 
1. The highest velocity in space found for any star is 494 km. for the ninth 
magnitude star A. G. Berlin 1366. Several other stars with larger parallaxes 
show values of nearly this amount. In all cases the components of motion in 
the plane of the galaxy exceed greatly those at right angles to it. 
2. For the stars as a whole we find the two components in the galactic plane 
very nearly equal and more than two and one-half times as great as the com- 
ponent perpendicular to it. We find a similar result from a consideration of 
the latitudes of the apices. Only 6 out of the 37 stars have apices with lati- 
tudes exceeding 30°. It is clear, therefore, that the influence of the galactic 
condensation is very marked upon the motion of these stars. 
3. Nearly an entire hemisphere in longitude is devoid of apices, the values all 
lying between 131° and 322°. 
