754 



TABLE 862.— REDUCTION OF VISUAL TO BOLOMETRIC MAGNITUDE* 



The bolometric corrections (B C) given in the table are added algebraically to visual 

 magnitudes. From tables by G. P. Kuiper, 278 slightly revised for O and 5 stars by same 

 author. The (effective) temperature, Te, scale of the O and early 5 stars is still to be re- 

 garded as provisional. The corrections for 5 — Fo stars are based on the stellar tem- 

 perature scale and on theoretical spectral -energy curves. For Fo — M 5 stars they are 

 based on radiometric observations by Pettit and Nicholson. 



* Prepared by G. P. Kuiper, Yerkes Observatory. 

 278 Astrophys. Journ., vol. 88, p. 446, 1938. 



TABLE 862A.— RUSSELL-HERTZSPRUNG DIAGRAM* 



Absolute magnitudes (ordinates) of 3,915 stars of different spectrum types (abscissae) 

 determined by the spectroscopic method by W. S. Adams and his associates (courtesy of 

 Mount Wilson Observatory, 1932). The diagram shows distinctly the division of types 

 G, and later, into giants (high-luminosity stars) and dwarfs (low-luminosity) with few 

 intermediate stars. The curve simulates the mirror image of the figure 7, and with the 

 addition of much new material confirms fully that first drawn by Russell in 1913. 



The majority of the stars may be divided into dwarfs, giants, and supergiants (a few 

 stars do appear to have luminosities intermediate between these classifications). The 

 luminosity of the dwarfs decreases regularly with advancing spectral type (reduced sur- 

 face temperature) ; it drops abruptly for the coolest. Among the giants the luminosity 

 decreases until about class F 5 and then increases with decreasing temperature at least as 

 far as the early subdivisions of class M. For supergiants, the luminosity does not appear 

 to change appreciably with spectral class. 



In the diagram, the concentration into vertical columns is purely an effect of rough 

 soectral classification. Most of the stars on this diagram belong to Population Type I 

 (Table 874). The white dwarfs occupy the lower left corner (Table 872). 



Kuiper 279 has more recently derived the empirical mass luminosity relation for (1) the 

 visual binaries, (2) some selected spectroscopic binaries, and (3) Trumpler's massive stars 

 in clusters. His diagram is reproduced in figure 33. Morgan, Keenan, and Kellman 28 ° 

 have presented a preliminary calibration of their luminosity classes in terms of visual ab- 

 solute magnitudes, which includes 5 stars ^s well as subclasses (intermediates between 

 giants and dwarfs and between giants and supergiants). 



* Prepared by Edith J. Tebo, Harvard College Observatory. 



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



280 An atlas of stellar spectra, p. 34, University of Chicago Press, 1943. 



SMITHSONIAN PHYSICAL TABLES 



