Stellar velocity distribution 



9 



In another paper 3 , however, the same examination was made for the class A stars. 

 Here a certain variation of the average peculiar velocity was noted not only in 

 terms of different distances from the assumed vertex but also in terms of galactic 

 latitudes. The vertex being situated in the plane of the Milky Way, this latter 

 variation is however quite evidently due to the former. He says about these fact 

 that »there seems to be no doubt, at least so far as the stars thus far observed are 

 concerned, that Class B radial velocities do not increase as their angular distances 

 from Kapteyn's vertices decrease, but that class A velocities do show increase; in 

 fact the preferential-motion effect is apparently stronger for class A stars than for 

 stars of classes F, G, K and M» . 



The radial velocity observations made at the Lick observatör}' during 1900 and 

 the following years were not totally published until 1913, and consequently only a 

 few authors have worked on this subject. The results obtained up to that time from 

 radial velocity results are clearly outlined by Campbell in his recently issued book 

 Stellar Motions. 



Catalogue of the observations of the velocities of the stars 

 in the line of sight. 



5. The catalogue of published radial velocities, which I have brought together, 

 is collected principally from the published records of the Lick and the Allegheny ob- 

 servatories. Most of the data are indeed obtained from the former observatory and 

 especially from the list of 915 stars with known radial velocities published by 

 Campbell in the Lick Observatör?/ Bulletin T. VII No. 229. In all, the catalogue 

 contains the radial motion of more than 1500 stars. 



The present investigation is consequently based on material containing in 

 the first instance modern information from the catalogue mentioned. Further the 

 lists of observations found in earlier publications of the Lick and Allegheny obser- 

 vatories are used, and with the help of publications of other observatories the material 

 is increased with such stars of which no records are to be found in the mentioned 

 Bulletins. Such stars are observed at the observatories of Bonn and Mount Wilson. 

 and are published in the Astronomische Nachrichten or the Astrophysical Journal. 



In some of the lists 2 , last referred to, the corrections to the »Lick system» 

 are also given. In such cases I have used the reduced values in the catalogue. 



6. By collecting the observations it was found that a fairly large number 

 of stars — between two or three hundred — have variable radial velocity. In the 

 cases when the stars are contained in Campbell's catalogues of spectroscopic binary 

 stars I have adopted the velocity of the centre of mass of the system, given there. 



1 Preliminary radial velocities of 212 brighter class A stars. Lick. Obs. Bull. VII. 211. p. 19. 



2 See F. Kdstnek: Radialgeschwindigkeiten von 227 Sternen des Spectraltypus F bis M, 

 beobachtet 1908 bis 1913 am Bonner 30 cm Refractor. Astr. Nachr. Bd 198 No. 4750. 



Lunds Universitets Årsskrift. N. F. Afd. 2. Bd 11. 2 



