750 TABLE 855.— MEAN ANNUAL PARALLAX FOR STARS* 



Part 1. — Stars of given visual magnitude and galactic latitude 



These tabular values have been obtained by combining and smoothing the secular paral- 

 laxes derived at Groningen and McCormick together with mean parallaxes for fainter 

 stars derived at Leiden. To obtain annual parallaxes from secular parallaxes a solar veloc- 

 ity of 19 kilometers per second has been assumed. Similarly the Leiden figures rest on cer- 

 tain assumptions as to the peculiar motions of faint stars. Recent studies of the space 

 motions of stars more than 500 parsecs from the plane of the galaxy indicate that the annual 

 parallaxes listed here may well be systematically too large for stars fainter than tenth 

 magnitude in the higher latitudes. 



Some idea of the dependence of the mean parallaxes on the sj>ectral type may be gained 

 from Part 2. Here the probable error of a secular parallax is approximately 0'-'001. 



Part 2. — Mean parallaxes according to spectral class for stars of visual magnitude 



10.0 (latitude 0° to 90°) 



Spectral Secular 



class parallax 



B 8 to A3 '.'007 



AS to F2 .011 



F 5 to G .022 



A'O to K2 .014 



gM to gM 8 .005 



* Prepared by A. N. Vyssotsky, University of Virginia. 



TABLE 856.— SPECTRUM CLASSES AND TEMPERATURES OF STARS* 



Observed Temperature by several methods, °K 



Heat Water-cell Heat index 



Spectral index absorption , A Water-cell Color Ioniza 



type Mag Mag X 0.555 fi X 0.529 n absorption index 270 tion 



B 05 .20 25000° 20000 



B5 01 .23 15500 15000 



A0 00 .26 10700 10000 



AS 02 .30 7500° 8530 8400 



F0 15 .36 6750° 7300° 6200 7500 7500 



FS 30 .41 5760 6160 5450 6470 7000 



dG il .42 5700 6100 5350 6000 



dG 5 39 .47 5350 5750 4920 5360 



DK 55 .54 4820 5100 4460 4910 



dKS 1.10 .76 3720 3980 3550 4150 1 



dMO 1.40 .87 3400 3650 3260 3600 1 



dM2 2.1 1.14 2870 3060 2780 3200 



qGO 47 .50 5000 5450 4700 5200 5600 



gGS 65 .60 4550 4870 4140 4620 5000 



gKO 90 .70 4020 4300 3750 4230 4000 



gKS 1.57 .93 3240 3480 3130 3580 3000 



(;M0 1.86 1.01 3030 3250 2980 3400 3000 



cjM2 2.2 1.14 2810 3000 2810 3200 



gMA 3.1 1.30 2400 2590 2550 2930 



gM6 4.2 1.46 2050 2200 2390 2750 



</M8 5.2 1.62 1780 2000 2250 



'Me Max 4.4 1.5 1990 2160 2350 



Mc Min 8.9 2.2 1830 



* Prepared by S. H. Nicholson, Mount Wilson Observatory. 

 270 Kuiper, G, P., Astrophys. Journ., vol. 88, p. 464. 1938. 

 t Payne, Stellar atmospheres, 1925. % Interpolated. 



SMITHSONIAN PHYSICAL TABLES 



