769 



TABLE 881.— PROPERTIES AND CLASSIFICATION OF STAR CLUSTERS* 



Star clusters fall into two distinctly different types : 



Globular. — Typical, Messier 13; open, Messier 4; elongated, Messier 19. Have strong 

 central condensations, rich in faint stars. Scattered widely in latitude, restricted in longi- 

 tude. Many variables— nearly 1,300 in 62 clusters. Radial velocities > 100 km/sec. All 

 more than 5,000, and one-third more than 50,000 light-years away. Very few new ones 

 found— about 100 known. Very definitely part of galaxy. Although concentrated toward 

 its plane, only 2 within 4° of it (obstruction by interstellar dust clouds). Diameters about 

 35 parsecs. Many stars, tens and hundreds of thousands. Many giants and supergiants 

 with maximum luminosity about — 2.5. 



Galactic. — Very varied: rich, Mil; irregular, M 35 ; nebulous, Pleiades; accidental, 

 M 103. Almost exclusively in Milky Way, all longitudes; apparently no variables. Radial 

 velocities rarely > 40 km/sec, generally less. Almost all less than 4,000 light-years dis- 

 tant. Almost exclusively in galactic region devoid of globulars. Tens and hundreds, 

 rarely thousands of stars. Hyades type, yellow stars as dominant as A type. Pleiades 

 type, almost all B's and A's, on Russell's main sequence. 



* Prepared by H. Shapley, Harvard University. 



Part 1. — Globular star clusters 



This table contains those with galactic latitudes > 20°, for which space absorption can 

 be evaluated and distance correctly estimated (also the giant cluster Omega Centauri in 

 lower latitude). 292 



Galactic Apparent Distance Absolute No. of 



, A v magni- (kilo- magni- vari- 



NGC RA (1900) Dec Long Lat tude parsecs) tude ables 

 h m 



104(47Tuc) . 19.6 — 72°38' 272° -45° (4.5) 7.6 —10.2 8 



288 47.8 —27 08 157 —88 8.96 14.5 — 6.8 2 



362 58.9 —71 23 268 —47 8.0 10.0 — 7.3 14 



1261 3 9.5 -55 36 237 -51.5 9.5 22 -7.2 



1851 5 10.8 -40 09 212 -34.5 7.72 14 - 8.1 3 



2419 7 31.4 +39 06 148 +26 11.51 56.2 —7.7 36 



4147 12 5.0 +19 06 226 +79 11.01 20.0 —5.5 4 



4590 (M 68) ... 12 34.2 -26 12 269 +36 9.12 13.5 —6.8 28 



5024 (M 53) ... 13 8.0 +18 42 305 +79 8.68 20.2 -7.8 42 



5053 13 11.5 +18 13 310 +78 10.9 17.4 -5.3 10 



5139(o.Cen) .. 13 20.8 -46 47 277 +15 (4.7:) 6.8 —10: 168 



5272 (M 3) .... 13 37.6 +28 53 8 +78 7.21 12.2 -8.2 186 



5466 14 1.0 +29 00 8 +72.5 10.39 17.0 - 5.8 18 



5634 14 24.4 —5 32 310 +48.5 10.8 32 —6.7 7 



5694 14 33.8 —26 36 299 +29 10.87 : 33.1 - 7.1 : 



5897 15 11.7 —20 39 312 +29 9.61 13.8 —6.5 



5904 (M 5) .... 15 13.5 +2 27 332 +46 7.04 10.1 -8.0 97 



6205 (M 13) ... 16 38.1 +36 39 27 +40 6.78 9.5 —8.1 15 



6218 (M 12) ... 16 42.0 —146 344 +25 7.95 8.3 —7.3 1 



6229 16 44.2 +47 42 40 +40 10.26 30 — 7.1 21 



6254 (M 10) ... 16 51.9 -3 57 343 +22 7.64 8.3 -7.6 2 



6341 (M 92) ... 17 14.1 +43 15 36 +35 7.30 10.3 —7.8 16 



6752 19 2.0 —60 48 303 -26.5 7.2 : 5.8 — 7.4 : 1 



6809 (M 55) ... 19 33.7 -31 10 336 -25 7.08 5.8 -7.7 2 



6864 (M 75) ...20 .2 —2212 347 -27 9.50 42 —8.9: 11 



6934 20 29.3 + 7 04 20 -20 10.01 18 - 7.0 51 



6981 (M 72) ...20 48.0 —12 55 3 -34 10.24 16.6 —6.6 31 



7006 20 56.8 +15 48 32 -21 11.45 44 -7.3 20 



7078 (M 15) ...2125.2 +1144 33 -28 7.33 11.5 —8.3 66 



7089 (M 2) ....2128.3 -116 21 -36 7.30 13.8 -8.5 17 



7492 23 3.1 —16 10 22 -64 12.33 25.1 - 4.7 9 



» a Shapley, Proc. Nat. Acad. Sci., vol. 30, p. 63, 1944; Pop. Astron., vol. 57, p. 9, 1949. For num- 

 ber of variables see Sawyer, Helen B., Publ. David Dunlap Obs., vol. 1, p. 388, 1947. 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



