( 484 ) 



Solution : 



(/(/„ =z + 0.0124 ; KndT= + 0.450 ; dKz=z f 0.054 ; 



Ke cos to' = + 0.292 ; Ke sin to' = — 0.489. 



from which we get the elements : 



g, = — 2.082 GM. ; an sin i — 24.264 ; e = 0.0235 ; 



(o' = 300^51' ; w' + i/o = 88°26' ; 



whereas the conjunction coincides perfectly with the principal mini- 

 mum, the (liference in time amounting to less than 0.01 days. 

 Evidently this is the principal minimum. This is in accordance with 

 the fact that the difference of the longitudes found for the two periastra 

 deviates but slightly from 180° (300°51' — 115°20'). This may be 

 partly due to a fortunate coincidence. 



Meanwhile the excentricity of the 2"*^ orbit is more than three 

 times smaller than that of the 1^\ while the velocity in the direction 

 towards the sun found for the whole system is 2 Geogr. miles 

 greater in the 2"^ case. 



If the latter difference is real, this acceleration would have caused a 

 shortening of theperiod between 1892 and 1897. As, howe\'er the measures 

 of 1892, according to the judgment of Prof. H. C. Vogel "nicht als 

 ganz einwurfsfrei angesehen werden können'* ^), we suspend our 

 judgment to the time that Prof. Belopolsky will again have taken 

 up his beautiful investigations on the spectrum of ji Lyrae, particularly 

 about the F- line. Already in 1897 he communicated his intention 

 to do so. 



If we put i = 90"', the semiaxes major are : 



a, =r 2056000 G. M. ; a, = 4307000 G. M. 

 From Kepler's third law we derive therefrom, roughly 



7??jrzrl7.1 sun's masses ; 7722 = 8.! sun's masses. 



17. In our opinion the preceding considerations justify the conclu- 

 sion that the data about /? Lyrae do not furnish a sufficient basis for 

 a decision about any change in the elements, in particular in the 

 excentricity. For the rest, owing to our ignorance on the circumstances 

 in such a close system, the adopted explanation of the light variation 

 can only claim to give a rough approximation — a rude imitation 

 of a very complicated mechanism. 



1) Ueber das Spectrum von |3 Lyrae. Sitzurgsb. Ak. Berlin. 1894 VI. 



