758 



TABLE 866A.— MASS LUMINOSITY RELATION* 



The mass-luminosity relation is shown in figure 33, which is based on data by G. P. 

 Kuiper." 81 Dots and open circles represent visual and spectroscopic binaries, each com- 

 ponent being shown separately. Crosses represent several visual binaries in the cluster of 

 the Hyades. Squares represent the white dwarfs. The symbol O stands for the sun. 



* Prepared by O. Struve, University of California, Berkeley. 

 281 Astrophys. Journ., vol. 88, p. 472, 1938. 



i/iO 1/5 1/2 'O 2 



Fig. 33.— The mass luminosity relation for stars. 



TABLE 867.— CLASSIFICATION OF NEBULAE 



Symbol 



I Galactic nebulae — A Planetaries P 



B Diffuse D 



(1) Predominantly luminous. DL 



(2) obscure . DO 



(3) Conspicuously mixed . . . DLO 



II Extragalactic nebulae — A Regular 



(1) Elliptical En 



1 to 7 shows ellipticity 



(2) Spirals 



(a) Normal spirals 5" 



( 1 ) Early Sa 



(2) Intermediate ... Sb 



(3) Late Sc 



(b) Barred spirals SB 



(1) Early SBa 



(2) Intermediate . . . SBc 



(3) Late SBc 



B Irregular Irr 



Extragalactic nebulae too faint to be classified, "Q" 



e. g. 

 N.G.C. 7662 



N.G.C. 6618 

 Barnard 92 

 N.G.C. 7023 



N.G.C. 3379 £0 



221 £2 



4611 £5 



" 2117 El 



N.G.C. 4594 

 " 2841 



" 5457 



N.G.C. 2859 

 " 3351 

 " 7479 



N.G.C. 4449 



SMITHSONIAN PHYSICAL TABLES 



