82 a. CENTAURI 



My measures (discarding the earlier ones), are as follows: — 



Date. Position Angle. Distance. 



1882-5 195°-7 lO^lS 



83-5 198 '3 11 .63 



85-47 200 -15 14 



86-8 201 -1 14 -83 



87-46 201 -72 15 "2 



I venture the following Ephemeris up to 1901 :— 



Date. 



Position Angle. 



Distance. 



1888 



202°-2 



15''-9 



89 



202 -9 



17 



90 



203 -6 



18 



91 



204 -3 



18 -9 



92 



205 



19 -7 



93 



205 -G 



20 -4 



94 



206 -2 



21 



95 



206 -7 



21 -5 



96 



207 -2 



21 -9 



97 



207 -8 



22 -3 



98 



208 -3 



22 -6 



99 



208 -8 



22 -8 



1900 



209 -3 



23 



01-7 



210 



23 -25 Maximum 

 elongation 



The actual mean angular distance of A..B ( = the semi-axis- 

 major of the real orbit), is 18"-6. The accepted parallax of 

 this star is 0-928". The actual mean distance of the companion 

 from its primary in terms of the earth's mean distance from the 

 sun will be 18"-6-^0"-928 = 20-043,— a distance slightly greater 

 than that of Uranus from the Sun, with a period almost identical. 

 If B revolved round our Sun at the above distance, its period 

 would be 89-732 of our years. Its actual period being only 

 about 84 years it is evident that the gravitational force of A 

 (and therefore its mass) is greater than that of our sun. How 

 much? The calculation is: — 89-732 years squared^ 83'7 

 years squared = 1-1493. That is, its mass is greater than that 

 of our Sun in the proportion of 1 to 1^ nearly. We cannot 

 thus estimate the mass of the smaller star B, there being no 

 visible object revolving round it. 



