762 TABLE 872.— WHITE DWARFS AND DEGENERATE STARS* 



Star m» CI Sp n p Mo = 1 



P 

 cgs 



V Ma 1 12.3 +.69 DF 2'.'98 '.'245 14.? .009 : 10 5 — 10 9 



o, Eridani B 9.4 .0: DA 4.08 .200 10.9 .018 7X10 4 



Sirius B 8.5 .. DF 1.32 .378 11.4 .034 5xl0 4 



He 3 12.0 -.80 DB .90 .066 11.1 .002: 10 6 — 10 7 



LDS 275 A 14.7 +.15 DC .35 012: 10 5 -10 6 



LDS 275 B 15.0 +.15 DC .35 012: 10 5 — 10 s 



L 39-44 17.2 +.2 : ... .57 005 : 10" 



W 489 14.8 +.77 DC 3.92 .129 15.4 .012: 10 s — 10 s 



LDS 678 A 12.0 —.14 DA .20 014 10 5 



p = parallax, n = proper motion, Sp = spectrum, m — magnitude, M = absolute magnitude. 



A representative selection of white dwarfs is given above, including the two stars for 

 which the masses are known (o 2 Eri B and Sirius B), the bluest white dwarf (He 3), the 

 reddest degenerate star (W 489), the only known double white dwarf (LDS 275), the 

 faintest known white dwarf (L 39-44) and a typical example of a white component of 

 red-white dwarf double (LDS 678 which has a red component of 13.7 vis with a color index 

 of +1.81). 



The values given for the radii and the densities (p) are in most cases very uncertain 

 estimates based on very approximate parallaxes and estimated masses. 



* Prepared by W. Luyten, University of Minnesota. 



TABLE 873.— LOW-DENSITY STARS, GIANTS* 



Star Type 



a Orionis cM 2 



a Scorpii A cM 2 



/3 Pegasi cjM 3 



a Tauri gK 5 



* Prepared by W. S. Adams, Mount Wilson Observatory. 



TABLE 874.— GIANT AND DWARF STARS* 



The table gives a list of typical supergiants, giants, and main-sequence stars. The rela- 

 tions between the absolute magnitudes and spectral types of the stars are conspicuous and 

 complicated. Along the main sequence M (visual) falls very rapidly from about — 4 for 

 class O to +14 for M 6. For identical spectra, the scatter about the mean is of the order 

 of ±l m . The normal giants form a sequence with M ranging from about for class G2 

 to — 1.5 for M8 with a somewhat greater scatter. Supergiants, with M from — 4 to — 7, 

 are found sparingly in all spectral classes. The white dwarfs, of which nearly 100 are 

 now known, form a widely separated group with spectra from A (or perhaps B) to G and 

 with M from +10 to +15. Subgiants, one or two magnitudes fainter than the normal 

 giants, are recognizable and the existence of other sequences is indicated by recent precise 

 work. 



The above discussion applies to stars of Population Type I, which is found in many 

 parts of the galaxy, the arms of spiral nebulae, and other regions where absorbing inter- 

 stellar material is present. Population II, in regions far from such matter, includes no 

 supergiants or bright blue stars and the relation of the sequences are different. This type 

 is found in the globular clusters, the elliptical nebulae, and the central regions of spiral 

 nebulae and the galaxy. Both types occur near the sun. 



The majority of the stars visible to the naked eye are giants, since these, being brighter, 

 can be seen at much greater distances. Classes F and G comprise the greatest percentage 

 of dwarf stars among those visible to the eye. The dwarf stars of classes K and M are 

 actually much more numerous per unit of volume, but are so faint that few of the former, 

 and none of the latter, are visible to the naked eye. 



* Prepared by R. E. Wilson, Mount Wilson Observatory, and E. M. Janssen, Harvard College 

 Observatory. 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



