CELESTIAL MECHANICS: LEUSCHNER 63 



(659) NESTOR, 1908 CS. 



Discovered by Wolf 1 at Heidelberg, 1908, March 23. 



From observations of 1908, March 25 and May 2, Ebell 2 computed 

 a circular orbit. From these Elements A it is evident that the planet 

 belongs to the Trojan group, Achilles type, and he notes the planet's 

 position is near a libration point (60 ahead of Jupiter). 



Preliminary elliptic Elements B, with an ephemeris for 1908, were- 

 computed by Ebell 3 from observations 1908, March 23, April 26, 

 and May 19. With Elements B Ebell 4 publishes an ephemeris for 1909. 



The improvement of Elements B was undertaken by Anderson. 5 

 Special perturbations due to Jupiter and Saturn were computed with 

 Elements B. Six normal places were formed from eleven observa- 

 tions extending from 1908, March 23 to 1912, September 9. 



The coefficients for the differential equations were computed by the 

 method given in Oppolzer. 6 The solution of the equations gave ab- 

 normal corrections when both or either normal places IV and V were 

 used. (IV and V are single observations). His final solution was 

 based on the first four normal places, (1908 to 1909). The resulting 

 Elements C were used to compute the special perturbations due to 

 Jupiter and Saturn and an ephemeris for 1913. 



Wolf reports 7 that Nestor cannot be found at ephemeris position. 



An ephemeris for 1914 based on Elements C, plus perturbations, 

 (disturbing planets not stated), was published by Andersen. 8 He 

 states no other observations for this planet are available. Reported 

 observations since 1909 do not appear to belong to Nestor. 9 



An ephemeris for 1915 based on Elements C by Anderson, was 

 published by Stromgren. 10 He states the correction to ephemeris, 

 based on an observation of 1914, December 20, is Aa +62 S , AS 7'. 6. 



Another attempt to improve the orbit of Nestor was made by An- 

 dersen 11 in 1917. In this attempt six normal places were formed from 

 observations in 1908, 1909, and 1917. The perturbations due to 

 Jupiter and Saturn were computed from Elements C, and the 

 normal places represented from the same elements. The starting 

 residuals for observation, 1908 and 1909, were small, (maximum 

 2".4) ; for the normal place V, (two observations of 1917), Aa cos 

 8 2008".8, AS +458".4; for the normal place VI, (two observa- 

 tions of 1917), Aa 1934".7, AS +392".2. The differential correc- 

 tions were computed as in the earlier work. 6 For resulting elements 

 see D. These elements left the following residuals for the V and VI 

 normal places: 



Aa cos S AS 



V 4".7 6".2 



VI +5.0 +7.2 



