Pub. Astron. Soc. Pacific, Volume 83, December 1971 LUMINOSITIES

Pub. Astron. Soc. Pacific, Volume 83, December 1971

LUMINOSITIES AND MOTIONS OF THE F-TYPE STARS. 1. LUMINOSITY AND METAL ABUNDANCE INDICES FOR DISK POPULATION STARS

O. J. EGGEN Mount Stromlo and Siding Spring Observatories, Research School of Physical Sciences The Australian National University Received 25 June 1971

Intermediate (uvbyß) and broad (UBV) band colors are now available for over 1000 bright (HR), F-type stars for which accurate apparent motions have also been determined. The present paper examines the luminosity ( a[ci] ) and metal abundance (8(17— B), and Δ [mi] ) parameters for Hyades group stars (§ II), other young disk stars including the Sirius group (§ IV), and old disk stars, including the Wolf 630 and ζ Herculis group members (§ V). A procedure is developed for computing luminosities from the intermediate-band indices for both young and old disk population objects. The comparison between photometric parallaxes and the group or trigonometric values indicate errors of not more than about 0Φ3 for the photometric luminosities. Ultrashort-period cepheids in the young disk population and a comparison between the metal abundance parameters Δ [mi] and 8 (U— B) are also briefly discussed. Key words: disk population stars — photometry — F-type stars

I. Introduction are on the Cape refractor system. Most of the If we define F-type stars as those with (B—V) southern stars have therefore been reobserved on between +0Γρ28(Ρ0) and +0^0(00), there are the UBV system with the 40-inch reflector at approximately 1200 such objects brighter than Siding Spring. Also, UBV results, mainly from visual magnitude 6^5 in the Catalogue of Bright observations with the 20-inch reflector at Palo- Stars (HR). Fifteen percent of these, mostly mar, are available for about 70 percent of the southern stars, have no radial velocity available northern stars. Both the northern (Eggen 1968) and the proper motions for 1 or 2 percent are and southern (e.g., Eggen 1970α) observations poorly determined. Intermediate-band (uvbyß) have been carefully tied to the UBV system. and broad-band (UBV) photometry is available The use of UBV photometry for the deter- for most of the remaining stars. The majority of mination of the chemical composition of main- the intermediate-band results are contained in sequence stars has been described elsewhere catalogs by Strömgren, Ferry, and Crawford (e.g. Eggen 1964 and references therein). The (preprint) and Crawford et al. (1966) for northern main difficulty, for the F-type stars, is in the stars and by Eggen and Stokes (in preparation) separation of abundance and gravity effects on for southern objects. Results for some bright the (17—B) colors. This difficulty is overcome southern stars have also been published by with the use of uvbyß photometry (e.g., Ström- Crawford, Barnes, and Golson (1970) and addi- gren 1963,1966; Crawford and Strömgren 1965). tional uvby observations of northern stars have The purpose of this paper is to reexamine the been obtained by Perry (1969) and Eggen (un- calibration of the photometric luminosity and published). The stars brighter than visual magni- abundance parameters of the disk population tude 5 have been observed on the UBV system with the large amount of data now available. by Johnson et al. (1966) and by Cousins (1967). The following standard nomenclature has been A few results by H. L. Johnson and his collabo- adopted. rators for fainter, northern stars are available in uii — (v—b) — (b — j/); metal line index the literature. Most of the southern stars have Ci = (u — v) — (v — b); Balmer been observed at the Cape Observatory, but un- discontinuity index fortunately, except for those in the equatorial [ci] = Ci — 0.2ß(b—y) = reddening free zone (δ = —10° to +10° ), the ultraviolet colors index 741

[mi] = Wh + 0.1S{b—y) = reddening free for Hyades main-sequence stars (e.g., Eggen and index Sandage 1959; Eggen 1965α) which is assumed to [u—b] = [ci] + £[771^ ; reddening free be also the relation for age-zero main-sequence index stars. The (β, ), (/3, [ci]) and (ß, ib-y)) Δ [rrii] = [mi] (Hyades main sequence)— relations for Hyades main-sequence stars in [mi] (star at a given/3 or (b — j/) Table I are derived by Crawford and Perry A[ci] = [ci] (star) — [ci] (zero-age main (1966); this (β , (b—y)) relation is also assumed to sequence) at a given β or {b —y) hold for age-zero maiiî-sequence stars. The The values of mi and Ci and all parameters based (β, [cj ) relation for age-zero main-sequence upon them will be given hereinafter in terms stars is derived from a more condensed version of 0^001. given by Strömgren (1963) and the (β. My) relation is based on the (B—V, My) relation derived II. Hyades Stars by Eggen (1965α) from the Hyades and Pleiades Table I contains the (U—B), (B—V) relation clusters.

TABLE I Photometric Parameters for Hyades and Age-Zero Main-Sequence Stars

Hyades Age-Zero Main Sequence ß [mi] [ci] [d] b-y B-V. My U-B F

2?81 229 846 804 131 +0^21 +2?55 +0?13 7.5 2.80 229 817 782 142 +0.225 +2.6 +0.12 7.5 2.79 227 790 760 152 +0.245 +2.7 +0.11 7.5 2.78 225 763 742 161 +0.255 +2.75 +0.105 7.5 2.77 223 738 704 170 +0.27 +2.8 +0.095 8.0 2.76 220 714 666 179 +0.28 +2.85 +0.085 8.0 2.75 219 690 650 188 +0.295 +2.9 +0.07 8.0 2.74 217 665 625 198 +0.31 +2.95 +0.06 8.5 2.73 216 630 598 208 +0.325 +3.0 +0.05 8.5 2.72 215 596 569 218 +0.34 +3.05 +0.03 9.6 2.71 215 562 540 229 +0.35 +3.1 +0.025 9.0 2.70 215 527 510 240 +0.365 +3.2 +0.02 9.5 2.69 216 485 480 252 +0.38 +3.3 +0.015 9.5 2.68 218 442 442 264 +0.405 +3.45 +0.01 10 2.67 220 406 406 279 +0.43 +3.65 +0.005 10.5 2.66 224 381 381 294 - +0.46 +3.85 0.00 11 2.65 230 356 356 309 +0.485 +4.0 +0.02 12 2.64 236 330 330 324 +0.51 +4.15 +0.04 13 2.63 245 307 307 340 +0.535 +4.35 +0.065 14.5 2.62 257 284 284 356 +0.56 +4.5 +0.09 16 2.61 271 265 265 373 +0.59 +4.7 +0.12 17.5 2.60 286 247 247 390 +0.62 +4.9 +0.155 19 (2.59) 302 231 231 407 +0.65 +5.1 +0.19 (21)

Table II contains the members of the Hyades is inapplicable. In addition to the photometric group, other than Hyades cluster members, parameters. Table II contains the following infor- amongst the stars in the Catalogue of Bright mation: Stars. An additional ten probable group mem- N,N: The source of the UBV and uvbyß bers have been omitted because they are so near results, respectively. The letters "C" and "J" the apex (or antapex) of the group motion that refer to UBV observations, already mentioned, proper motion contributed negligibly to the V- by Cousins or by Johnson and their collaborators. velocity and therefore the concept of a group Observations with the 20-inch Palomar reflector parallax, derived from forcing V = —16.8 km/sec. or 40-inch Siding Spring reflector are indicated

TABLE II Hyades Group Members

HP V£ B-V U-B N,N U W m— M HR b-y [mi] [ci] dU dV dW μδ Sp. AR (km/sec) (O'.'OOl) 4757 5^56 +0?36 +0^055 2 / S + 33 -16.8 - 5 + 84 + 5.9 4^87 230/1* 240 211 671 2.700 + 3 - 2 0 - 4 gFO 2.9 6680 6.25 +0.40 0.00 2 / S + 41 -16. 8 -10 + 200 + 15.0 3.27 327 268 208 468 2.677 + 7 - 6 - 1 - 30 F5 IV 1.0 7570 4.96 +0.57 +0.09 C,2 + 33 -16.8 -11 +665 + 11.5 0.28 370 380 245 343 2.625 + 30 -12 0 + 186 F8 V 0.26 8673 6.34 +0.48 -0.01 3,S + 36 -16. 8 -15 +225 + 16.9 2.69 410 314 220 386 2.651 + 8 - 8 - 2 - 84 dF5 0.8 8774 6.27 +0.45 0.00 2, S + 42 -16. 8 - 3 + 155 + 14.5 3.82 415 296 231 402 2.656 + 6 - 5 + 1 - 9 F5 1.4 13871 5.80 +0.44 0.00 2 , S + 39 -16.8 -12 + 173 +26.0 3.10 656 288 223 440 2.655 + 5 - 7 0 - 59 dF3 0.65 15634 6.49 +0.29 +0.04 2,2 + 40 -16. 8 - 9 + 84 +25.0 4.65 733 184 217 773 2.765 + 4 - 1 + 2 + 36 dA9 1.3 17094 4.27 +0.31 +0.075 CJ,S + 38 -16.8 - 9 +284 +28.8 1.77 813 189 221 724 2.743 + 8 -10 + 5 - 29 F0 IV 0.21 18404 5.80 +0.40 0.00 4,S + 41 -16. 8 - 3 +236 + 28.5 2.40 878 277 216 428 2.676 + 6 - 8 + 4 - 29 dF5 0.36 18692 5.67 +0.39 + 0.01 2,2 + 35 -16.8 -10 + 182 +27.0 2.30 901 267 217 479 2.702 + 8 - 3 + 5 + 89 A9 0.9 2 0 313A 5.70 +0.32 +0.19 3,2 + 33 -16.8 - 4 + 76 + 3: 4.33 981* 157 220 810 2.770 + 5 - 2 0 + 74 F0 III 3.7 Β 8.06 +0.42 +0.04 2,2 281 213 448 2.674 20675 5.93 +0.46 0.00 2,S + 42 -16. 8 + 6 + 187 +24.7 3.02 1001 293 220 436 2.653 + 5 + 2 - 67 dF5 0.7 23010 6.48 +0.38 +0.02 2,4 +51 -16.8 + 11 + 78 +28.5 5.20 1125 240 233 696 2.704 + 3 - 1 + 3 + 45 F2 IV 2.6 24546 5.30 +0.40 0.00 2 , S + 40 -16.8 - 9 + 97 +26.7 3.35 1210* 279 209 434 2.6 80 + 4 - 6 - 2 -127 F5 IV 0.8 25998 5.52 +0.54 0.00 6,S +33 -16.8 - 8 + 166 +25.5 1.68 1278* 334 240 306 2.641 + 4 -12 - 2 -200 dF7 0.29 25893 7.15 +0.85 +0.48 4, K2 30144 6.34 +0.32 +0.01 1,S + 34 -16.8 + 2 + 81 +21.9 3.50 1515 199 213 620 2.740 + 3 - 5 0 -100 F0 0.8 30912 5.97 +0.355 +0.155 2,S + 40 -16. 8 0 + 52 + 38.0 4.33 1554 227 225 799 2.702 0 - 3 + 1 - 35 F2 0.03 40292 5.28 +0.32 0.00 C, 5 + 40 -16.8 -11 - 22 +24.2 2.40: 2094* 177 216 723 2.749 + 11 + 2 + 1 +242 F0 V 5.4 61064 5.13 +0.44 +0.08 3,S +50 -16.8 -18 - 69 + 46.0 4.97 2927* 289 221 595 2.657 + 2 + 1 -25 + 15 F5 III 4.8

TABLE II (Continued)

HD Ve B-V U-B Ν, Ν υ V W m— M HR b~tj [mi] [Ci] dU dV dW Μ δ Sp. AR (km/sec) (O'.'OOl) 69997 6.32 +0.33 +0.14 C,S + 37 -16.8 + 2 - 44 + 35.ö 3265 196 265 747 2.753 + 2 + 1 - 1 + 33 F2 III 5.9 76292 5.89 +0.35 +0.055 2,S + 39 -16.8 - 7 - 81 +25.9 4.55 3546 232 221 664 2.699 + 2 - 2 - 3 - 50 gF3 0.01 76943 3^5 J,S + 41 -16.8 - 6 -435 +26.4 0.90 3579* 2 86 224 442 2.670 +14 -11 -16 -254 F5 V 0.00 77370 5.16 +0.41 +0.005 2,2 + 44 -16.8 + 5 -173 + 10.6 2.40 3598 270 209 463 2.663 + 15 - 2 + 2 +272 dF4 4.6 78366 5.99 +0.57 +0.0 4 3,S +32 -16.8 + 2 -184 +27.2 1.77 3625 377 266 236 2.601 + 5 - 6 - 7 -126 dGO 0.23 82554 5.31 +0.445 +0.01 2.2 + 39 -16.8 -40 -141 + 7.0 3.36 3795 297 214 570 2.652 + 8 - 4 - 8 + 130 aF2 2.3 89254 5.24 +0.32 +0.09 5.3 + 30 -16.8 - 8 -160 + 15.2 3.10 4042 189 235 777 2.765 + 6 - 1 - 4 + 1 Fl III 5.8 104671 4.30 +0.28 +0.03 2,Cr + 38 -16.8 - 7 -146 - 2.4 3.90 4599* 180 (175) 837 2.718 + 6 - 3 - 1 + 1 Am 2.8 107326 6.12 +0.30 +0.06 2,S + 40 -16.8 + 3 -145 + 8.0 3.96 4694 193 211 723 2.738: + 6 - 3 - 1 + 18 dA8 0.30 107904 6.08 +0.35 + 0.18 4,8 + 42 -16.8 - 2 - 77 + 5.0 5.47 4715 226 219 788 2.707 + 3 - 1 - 1 + 9 F0 III 1.2 108506 6.21 +0.43 +0.11 3,S + 40 -16 i 8 -15 - 90 -12.0 5.20 4746 276 226 593 2.673 + 4 - 2 0 - 5 A8 2.3 110385 6.04 +0.40 +0.07 2,3 + 35 -16.8 - 1 -170 - 2.8 3.38 4827 254 217 649 2.696 + 7 - 4 0 + 12 F2 1.7 111998 6.10 +0.50 +0.02 C,S + 31 -16.8 - 6 -260 - 7.1 2.30 4891 320 223 370 2.646 + 10 - 7 0 dF6 0.6 113022 6.20 +0.45 0.00 6 ,S + 45 -16.8 + 4 -230 + 0.8 3.17 4926 288 230 388 2.659 + 10 - 4 + 1 + 56 F7 V 0.29 115604 4.71 +0.30 +0.205 2,S + 35 -16.8 + 10 -125 + 7.5 4.09 5017 180 264 877 2.778 + 5 - 3 0 + 17 F0 II-III 0.9 119756 4.23 +0.38 0.00 JC, 2 + 41 -16.8 -13 -460 -21.8 1.28 5168* 255 210 500 2.691 + 15 -17 - 1 -147 F2 III 0.36 126504 5.82 +0.31 +0.13 C,1 + 46 -16. 8 -10 -146 -25.6 3.68 5401 187 217 713 2.785 + 5 - 6 - 1 - 76 Am 1.0 127739 5.92 + 0.37 +0.0 3 2,S + 33 -16.8 + 2 -133 -12.4 3.68 5434 237 217 599 2.699 + 5 - 3 + 3 + 36 dF2 0.7 128617 6.39 +0.445 +0.01 2,3 + 34 -16.8 - 9 -183 -17.0 2.62 5458 280 215 502 2.685 + 6 - 8 - 2 -126 F6 IV-V 0.8 129723 6.48 + 0.31 +0.07 C, 2 + 49 -16.8 + 4 -100 -14.0 4.67 5491 186 248 673 2.797 + 5 - 3 0 - 73 F0 III 2.3 131117 6 .29 + 0.60 +0.13 2,3 + 44 -16.8 -327 -26.8 2.00 5542 383 264 375 2.635 + 9 -11 - 36 dGl 0.38

TABLE II {Continued) HD _Ve_ B-V U-B N,N U ν W m— M HR b-υ [mi] [cj dU dV dW ^ 8 Sp. AR (km/sec) (O'.'OOl) 144284 4.03 +0.52 +0.10 J,S + 39 -16. 8 + 5 -323 - 8.5 Λο 5986* 354 238 389 2.639 +21 - 6 + 6 + 337 F8 IV-V 1.3 147449 4.82 +0.335 +0.025 JC,S + 45 -16.8 -10 -156 -45.5 1.88 6093 220 217 605 2.726 + 3 - 3 + 6 + 50 F0 V 0.7 150557 5.73 +0.33 +0.06 3,S + 48 -16.8 - 3 -103 -45.4 3.12 6205 206 212 706 2.723 + 2 - 1 + 5 + 53 dF2 2.5 154783 5^93 +0^31 +0^16 2 , 3 +33 -16.8 -15 - 7 -32.2 4.47 6366 159 261 811 2.807 0 - 3 - 1 - 62 F0 III 0.40 155203 3.34 +0.405 +0.08 JC,2 + 34 -16.8 -22 + 27 -27.0 2.00 6380 276 210 684 2.690 + 3 - 9 - 9 -281 F0 IV 0.28 156098 5.49 +0.52 +0.0 4 2.2 + 38 -16.8 + 8 - 91 -35.8 3.34 6409 327 231 461 2.640 + 1 - 4 + 2 - 52 F5 0.26 161149 6.24 +0.42 +0.17 3.3 + 38 -16.8 -11 0 -42.4 4.35 6604 273 217 743 2.701 + 1 + 1 + 1 + 29 dF4 6.1 172748 4.70 +0.35 +0.14 C , 3 + 42 -16. 8 - 1 + 13 -45.3 3.60: 7020* 217 235 780 2.750 0 0 - 1 0 F 3 HI-IV 14.0 174209 6.30 +0.40 +0.05 2,2 + 32 -16.8 + 6 - 18 -35.4 3.58 7088 239 217 672 2.697 0 - 2 0 - 33 A7 III 1.3 177474/5 4.25 +0.51 +0.01 2,2 +54 -16.8 + 2 + 98 -52.0 1.05 7226/7* 338 230 268 2.632 + 3 -10 -269 F8 V 0.00 182900 5.77 +0.45 +0.035 3,S + 32 -16.8 + 5 + 7 -33. 8 3.29 7389 302 223 481 2.659 + 2 + 2 + 1 + 62 F6 III 4.0 192886 6.12 +0.46 -0.01 C, 2 + 44 -16.8 - 6 + 190 -30. 8 2.27 7749 309 213 371 2.660 + 7 - 7 - 8 -185 F6 V 0.16 195627 4.75 +0.29 +0.04 C, 2 +31 -16. 8 + 5 + 80 -20.1 2.47 7848 177 216 712 2.776 + 5 - 7 - 2 -178 FO V 0.44 200525 5.68 +0.59 +0.09 C, 2 + 41 -16.8 -11 + 444 -10.0 1.15 8061 375 281 218 2.644 +20 -13 -10 -334 G3 IV 0.40 206088 3.67 +0.32 +0.20 JC, 2 + 33 -16.8 + 7 + 190 -31.2 1.93 8278 183 287 780 2.780 + 6 - 2 - 6 - 21 Am? 2.4 212754 5.76 +0.515 + 0.03 6,S +56 -16.8 -12 +286 -17.8 3.09 8548 330 248 351 2.622 + 12 - 1 - 6 + 52 dF5 5.0 213198 6.45 +0.33 +0.04 3,2 +53 -16. 8 -21 + 164 -10.7 4.37 8565 221 213 711 2.743 + 7 - 2 - 4 + 2 dFl 2.7 214470 5.10 +0.39 + 0.15 2,1 + 51 -16.8 -21 +166 + 0.1 4.25 8615 2 40 223 692 2.690 + 7 - 2 - 3 + 28 F4 III 3.8 217877 6.68 +0.58 + 0.05 C, 2 + 44 -16.8 + 315 -13.6 2.41 8772 378 254 283 2.612 + 14 - 3 + 38 G3 V 1.6 218060AB 5.42 +0.31 +0.04 4,S + 43 -16.8 + 128 -15.0 4.27 8782* 186 209 712 2.738 + 6 - 1 + 14 F2 V 3.5 218235 6.16 +0.445 +0.02 4,S +48 -16. 8 +216 -12.0 3.32 8788 287 2 40 421 2.660 +10 - 2 + 66 dF4 2.5

TABLE II {Continued) HD Ve Β— V U-Β Ν,Ν U V W μ α Ρ m—M HR [mi] [ci] β dU dV dW μ δ Sp. AR (km/sec) (Ο'.'001) 218261 6.45 + 0.54 +0.02 3, S + 35 -16.8 -11 + 287 - 6.0 2.35 8792 353 246 293 2.612 + 12 - 4 - 5 + 8 dGO 1.9 222451 6.25 +0.40 -0.01 5 , S+ + 41 -16. 8 - 8 + 225 - 0.2 3.08 8977 270 213 460 2.6 80 + 10 - 4 - 2 + 27 F5 2.2

* NOTES TO TABLE II HR 230/1 Equal components separated by 4". 5. 981 The components are separated by 16". The bright star is a spectroscopic binary. 1210 Spectroscopic binary with components differing by 0Φ25; F = 30d. 1278 The distant companion, 12', is physical and itself double with a 9m companion 1" distant. 2094 Too little dependence of V on distance for accurate distance determination. 2927 (L/, V, W) vectors in Royal Obs. Bull. No. 51 are incorrect. 3579 Visual binary with companion 2m fainter. 4599 Spectroscopic binary, Ρ = 24d. The magnitude difference has been assumed here to be zero but may be as large as 0Φ5. 5168 Spectroscopic binary; Ρ = 10d. 5986 Spectroscopic binary; F = 3d. 7020 8 Set variable; F = 0^19. Very small dependence of V on distance. 7226/7 Equal components with period near 200 years. 8782 Equal components, short period. by the number of available observations. Inter- certainty in the radial velocity is more serious mediate-band results by Strömgren and Craw- than that in the proper motions and the values of ford and their collaborators, noted above, are Afí give some indication of the accuracy of the designated by "S" in Table I, and the unpublished distance determinations. These values are southern-hemisphere results are indicated by the derived from Afí = V(p)lDV where V(p) is the number of available observations. percentage of ρ that contributes to V and DV is {UVW\ {dU, dV, dW): The components of the the change of V for a 100-parsec change in dis- space motion and their change for a ten-parsec tance. Except for one important star, HR 7020 increase in the listed distance. A median value (δ Scuti), only objects with AR less than 6 par- of V for the Hyades cluster members of —16.8 secs are included in Table II. In only one or two km/sec has been adopted as the group motion. cases (HR 2094, HR 7020) do the values of Afí lead to uncertainties of 0^5 in the luminosity and μα, μ8 and ρ: The components of the proper motion and the radial velocity. The proper mo- in the majority of cases this uncertainty is less tions are mainly recent determinations based on than 0^1. all available positions. The radial velocities are The stars of Table II are shown in the the mean values from all available determina- (B—V,Mv) plane in Figure 1 and in the tions and are on the system of the General ([mi] ,/3) plane of Figure 2. The continuous Catalogue of Radial Velocities. curve in Figure 1 is the age-zero main sequence Sp: The spectral types are mainly from the and in Figure 2 is the ([mj ,/3) relation for Catalogue of Bright Stars, although a few more Hyades cluster stars from Table I. Two features recent determinations are included. of Figure 1 should be noted. First, the Hyades m—M, Afí: The modulus resulting from the group obviously contains older stars than either group parallax and the change in the resulting the Hyades or Praesepe clusters, which, in the distance (in parsecs) caused by a 1-km/sec range of colors discussed here, contain no stars change in the radial velocity. In general, the un- that deviate more than about 0^5 from the main

Fig. 1 — The Hyades group stars, other than Hyades and Praesepe cluster members, in the (My, B—V) plane. The G-type giant (HD 72779 = 35 Cnc) in the Praesepe cluster is indicated by a plus sign. The continuous curve Fig. 2 — The Hyades group members in the ([mi], β) represents the age-zero main sequence. plane. The numbered, strong-lined objects are mainly Am stars or short-period variables. The continuous curve represents the relation for Hyades cluster stars. sequence. And secondly, the break in the distribution of stars on the main sequence near (B—V) = +0^32 to +0^37 is also present in the Hyades and Praesepe clusters, each of which contains one main-sequence star in this color range. The same discontinuity in the distribution of main-sequence stars has also previously been noted in the young clusters associated with the Pleiades group (e.g., Eggen 1965α, Fig. 13). The standard ((7-ß , B—V) relation is shown in the two panels of Figure 3 as a continuous curve. The individual Hyades cluster stars, not known to be double, from which the standard relation is obtained, are shown as open circles in Figure 3a. The individual members of the Praesepe cluster (Johnson 1952), shown as filled circles in Figure 3a, indicate some systematic deviation from this relation, especially for stars redder than (B—V) = +0^45. However, the combination of a small reddening effect, E(B— V) = +0^1 or +Cr02, and the nonnegligible uncertainty of the results for these stars, for which V= 10m, could account for this deviation. Johnson finds a probable error of the (U—B) results of between 0^01 and 0^02, from the in- Fig. 3 — The {U—B, B—V) relation for main-sequence ternal agreement of the observations and from Hyades group (Table II) stars (b) and the Hyades and the tie-in with the fundamental UBV system. Praesepe cluster members (a). The continuous curve in both panels is the standard relation for Hyades cluster The stars in Table II within 0^5 of the Hyades stars (Table I). main sequence are shown in Figure 3b as open circles. Again the small deviations from the amounts of reddening and small photometric standard relation could result from small errors.

Some success has been achieved in calibrating groups on the basis of the values of β. A few observed ultraviolet deficiencies in F-type stars stars, indicated by colons, are omitted in the with luminosity (Eggen 1966), but for displace- following discussion for reasons given at the end ments less than lm from the main sequence, the of the table. Strömgren found that F = accuracy is low (e.g., Eggen 1970&, Fig. 9). AMv/A[ci] varied with decreasing tempera- Strömgren (e.g., 1963, 1966) has found that dis- ture from near 9 for )8 = 2.8 to near 10 at )8 = 2.7 placements from the main sequence of F-type and 17.5 at β = 2.6. To offset the effect in these stars are closely correlated with values of correlations of large values of Δ [τη^ for peculiar A[ci]. The displacements of the stars in and metallic-line stars Strömgren (1966) has Table II from the age-zero main sequence, Δ My, suggested that Δ[ο1] be corrected by including and from the ([mj ,/3) and ([cj ,/3) relations some fraction of Δ [mi]. The present results for Hyades main-sequence stars are listed in lead to the following procedure; (a) to avoid Table III where they are divided into four confusion with observational error, only values

TABLE III Displacements of the Stars in Table II from Various Correlations of the Photometric Parameters HR b—y A[mi] a[ci] aMv HR ß b—y A[mi] Aid] AMy > 2.72 = 2.65-2.66 6366 2.807 159 -32 + 78 + 1710 327 2.677 268 + 11 + 15 5491 2.797 186 -20 - 62 +0.85 878 2.676 277 + 3 0 +0.15 8278 2 .780 183 -62 + 162 + 1.0 981B 2.674 281 + 6 + 24 -0.2 5017 2.IIS 180 -39 +221 +2.1 4746 2.673 276 - 7 + 176 +2.6 981A 2.770 157 + 3 +106 + 1.45 3579 2.670 286 - 4 36 +0.6 7848 2 .766 177 + 8 - 15 +0.5 3598 2.663 270 + 14 46 + 1.05 733 2.765 184 + 5 + 88 + 1.0 7749 .660 309 + 11 32 0.0 4042 2.765 189 -13 + 118 +0.75 8788 .660 287 -16 72 + 1.0 3265 2 .753 196 -46 + 184 + 1.0 4926 .659 288 - 5 9 + 0.8 7020* 2.750 217 -16 +162 + 1.8: 7389 .659 302 + 2 + 102 + 1.35 2094* 2.749 177 + 3 + 75 0.0: 2927 .657 2 89 + 5 +221 + 3.75 813 2.743 189 - 3 + 91 + 0.45 415 .656 296 - 5 + 31 + 1.45 8565 2.743 221 + 5 + 78 +0 . 8 656 2.655 288 + 4 + 72 + 1.2 1515 2.740 199 + 4 - 5 +0.1 1001 2.653 293 + 8 + 73 + 1.05 4694 2.738 193 + 6 +103 +0.8 3795 2.652 297 + 15 +179 +2.0 8782 2.738 186 + 8 + 92 + 1.05 410 2.651 296 + 9 + 25 +0.35 6093 2.726 220 - 1 + 19 +0.05 6205 2 .723 206 + 3 + 130 +0.45 = 2.60-2.65 = 2.68-2.72 4841 2.646 320 + 9 + 24 +0.25 8061 2.644 375 -47 - 28 +0.4 4599* 2 .718 180 + 40 + 194 +1.9 1278 2.641 334 - 4 - 27 +0.25 4715 .707 226 - 4 +257 +2.55 6409 2.640 327 + 5 + 131 + 2.0 1125 .704 2 40 -18 +210 + 1. 85 5986* 2.639 354 - 1 + 61 + 1.5: 901 .702 267 - 2 - 27 -0.2 5542 2.635 383 -24 + 104 + 0.2 1554 . 702 227 -12 +298 + 1.55 7226/7 2.632 338 +13 - 70 +0.35 6604* .701 273 - 2 +230 + 1.3: 370 2.625 380 + 6 47 -0.25 230/1 .700 240 + 4 + 161 + 1.75 8548 2.622 330 + 7 62 + 1.8 5434 2.699 237 - 2 + 92 +0.95 8772 2.612 378 + 14 14 +0.4 3546 2.699 232 - 6 +157 + 1.85 8792 2.612 353 +22 18 +0.5 7088 2.697 239 - 2 + 171 + 0.5 3625 2.601 377 + 18 49 +0.5 4827 2.696 254 - 2 + 151 + 0.6 5168 2 .691 255 + 6 + 17 +0.35 6380 2.690 276 + 6 +204 + 1.95 8615 2 .690 240 - 7 +212 +2. 45 5458 2.685 280 + 2 + 41 -0.2 1210* 2.680 279 + 9: - 8: +0.75: 8977 2.680 270 + 5 + 18 + 0 . 3

* Notes to Table III HR 1210 Am = 0.2 5 HR 2094 AR = 5.4 HR 4599 Ap HR 5986 Sp.B. HR 6604 AR = 6.1 HR 7020 AR =14.0

© Astronomical Society of the Pacific · Provided by the NASA Astrophysics Data Syí F-TYPE STARS 749 of Δ [mi] greater than 0.10 are considered three stars, HR1554, HR4827, and HR7088. meaningful and (b) larger values of A[m1] are These three stars might be dismissed as possible used to correct Δ [cj by —2 Δ [mi]. All values nonmembers except for the fact that two, of A[ci] for Hyades-like stars will be so cor- HR4287 and HR 7088, in addition to having the rected. The correlations of A[ci] and Δ My for same values of Δ My, near +0^5, amd the same the stars in Table III are shown in Figure 4. luminosity. My = +2^7, are also nearly identi- Stars with Δ[ιη1] > +10 are shown as filled cal in both broad- and intermediate-band colors. circles and with Δ[/?ι1] < —10 as crosses. The Both stars are also similar to HR 1210 which has correlation is excellent for all the stars in Figure been omitted from Figure 4 because of the 4c and the majority in Figure 4b. Although slight inequality of the two components (spec- there is considerable scatter in the other two troscopic binary, Am = 0^25). No evidence of panels of Figure 4, the mean residuals from a variable radial velocity for HR 4287 or HR 7088 mean correlation would not very much exceed has been published. The remaining twelve stars the probable error of 0^2 to 0^3 found by Ström- in Figure 4b follow closely the relation gren (1966) for a given star. The variation in the Δ My = 9.5 ( Δ [cj -l· 20) with an rms deviation closeness of the correlations in the various of 0^2. panels of Figure 4 may represent, in the majority B. The correlation in Figure 4c gives the rela- of cases, effects of strong lines or microturbulence tion ΔΛ^ = 10.5 ( Δ [ex] +20) with an rms occurring in various spectral regions. Some deviation of only 0^1. The small zero-point dis- particular cases that could repay closer spec- placement in Δ[(;ι] may arise from the use of troscopic investigation are discussed in the fol- the [ci] relation for the age-zero main sequence lowing paragraphs. that was derived by Strömgren from the lower A. The very close correlation between Δ [ci] envelope in the {b—y,[ci]) plane for field and Δ My in Figure 4b is grossly violated by stars and therefore contaminated by the presence

1 1 1 1 Τ Γ [ I I T ·' 1 r~ β =2-60-2-65 β= 2-65-2-68 ΔΜ ν (d) (c) +3 0 /

+2 / o · 0 / 0 • /x Fig. 4 — The correlation be- +1 0 tween displacement above the /o age-zero main sequence, AMy, 0 and A[ci] for Hyades group o O x /0 stars in Table II. The stars are 0 0 o divided into four groups on the ι ι I I 1 I basis of the values of β. The 0 s straight lines are discussed in ß>212 β= 2-68-2-72 / the text. ' (a) χ: ω o>, o χ +1 Χ χ x o Οχ 0 / o o o / 0 0 J* o o o I, ,,1_. 1,..., 1 ,J ,L, 1 1 1 1 1 1 1 _ Ap-i] 0 100 200 0 100 200 300

© Astronomical Society of the Pacific · Provided by the NASA Astrophysics Data System 750 O. J. EGGEN of some mildly metal-deficient stars. The devia- themselves are mainly the result of uncertainties tion of the largest value of Δ My probably in- in the distance. Regarding only the largest dicates a departure from linearity for deviations values of AMy in Figure 4d, and assuming from the main sequence of more than 2™5 or 3m. the same zero-point correction to [¢^] as was C. The(A[ci] , AMy) relation in Figure 4a is found in Figure 4abc, we derive the relation apparently complicated by the presence of seven AMv= 16 (Aid] + 20). stars showing large negative values of A[m1]. III. Variable Stars These stars, many of which are ultrashort-period, The Hyades group members in Table II that small-amplitude variables, will be discussed in are brighter than My = +2m are listed in the next section. The best fit to the points in the Table IV together with the computed luminos- figure is Δ My = 8 ( Δ[θι] + 20) with one ities based on values of Δ [οχ] and the precepts star, HR5491, giving the large displacement of discussed in the previous section; values of the m l and the others showing an rms deviation of spectral types are also listed. Omitting the two 0^35. Attention should be drawn to HR 5491 stars (HR 6604 and HR 7020) with large values which has greatly distorted values of both [ci] of AR, as discussed in Table II, and HR 1554 and [mi]. This star is a newly discovered vari- and HR 2927, already noted as discordant, the able, discussed in the next section, and the rms deviation for an individual value of the spectrum may be of interest. difference between the observed and computed D. The scatter in Figure 4d, especially for luminosities is 0^3. Four of the 20 stars in Table small values of Δ My, is probably connected with III are known ultrashort-period cepheids; the virtual collapse of the β index near values of HR 3265 (0

TABLE IV Hyades Group Members with My > + 2n Obs. Comp. HR Β-V A[Ci] My My o-c SP Var?

230/1 + 0^36 + 161 +1^45 +1¾ -0.05 gFO CON 733 +0.29 + 88 +1.85 +2.0 -0.15 dA9 981 +0.32 +106 + 1.35 + 1.8 -0.45 F0 III CON 1125 +0.38 +210 + 1.3 +0.95 +0.35 F2 IV 1554 +0.355 +283 + 1.65 + 0.35 (+1.3) F2 CON 2927 + 0.44 +222 +0.15 + 1.35 F5 III Var?* 3265 + 0.33 + 184 + 1.9 + 1.3 +0.6 F2 III Var 3546 + 0.35 +157 +1.35 + 1.5 -0.15 gF3 3795 +0.445 + 179 + 1.95 + 1.9 +0 . 05 gF2 4599 + 0.28 + 194 +1.15 + 1.05 +0.1 Am 4715 +0.35 +257 + 0.6 +0.55 +0.05 F0 III Var 4746 + 0.43 + 176 + 1.0 + 1.5 -0.5 A8 Var?* 5017 + 0.30 +221 +0.6 +0.85 -0.25 F0 II-III Var 5491 +0.31 - 62 + 1.8 F0 III Var* 6366 +0.31 + 78 +1.45 +1/75 -0.3 F0 III CON 6380 +0.405 +204 + 1.35 + 1.1 +0.25 F0 IV CON 6604 +0.42 +230 + 1.9 +0.8 dF4 CON 7020 +0.35 + 162 + 1.1: + 1.45 -0.35: F3 III Var 8278 +0.32 + 162 +1.75 +1.3 +0.45 Apm 8615 +0.39 +212 +0. 85 + 1.1 -0.25 F4 III CON

* New Variables

HR 2927, HR 4746, and HR5491 have been Strömgren 1966). The procedure of computing examined for variability on the basis of their luminosities adopted here is then as follows: position in Figure 1. Five stars in Table IV have 1. Values of Δ[^1] and A[m1] are derived been found constant (CON), three (HR 230/1, from the observed colors and the standard values HR 6604, and HR 8615) by Breger (1969), one of [rrii] and [cj for the observed β, as listed in (HR 1554) by Danziger and Dickens (1967), and Table I. two (HR6366 and HR6380) from unpublished 2. Valuesof Δ [Ci] 1 = Δ [cj + 20 + 2 Δ [mj results with the 40-inch reflector. The observa- are formed. In the Hyades group, discussed tions will be published in detail elsewhere, but above, the value of Δ[7η1] was known to be HR 2927 and HR 4746 probably have very small zero and the strong-lined Am and variable (0^1) amplitude, semiregular light variations in stars which were marked by large apparent periods near 1¾ hours, and HR 5491 has an values of Δ[7η1] were found to fit the correla- amplitude near 0^02 and a period near 0^13. Most tions between Δ My and Δ[^1] better if Δ[βι] of the variables show large negative values of was corrected by — 2Δ[?η1]. However, in dis- Δ [mi] which, as Strömgren (1966) has noted, cussing stars in the general field this procedure is are also characteristic of metallic-line stars. The not practical; but, since such stars are rare, the strong lines that lead to these values of Δ [mj resulting error, which will amount to 4 Δ [mi] would appear to be a common feature of the m the value of Δ [ci] ^ will not often occur. ultrashort-period cepheids and metallic-line 3. Departures from the (β, My) main se- stars although Breger (1970) has suggested that quence in Table I are computed from Δ My = small-amplitude, ultrashort-period cepheids and F Δ[ο ] 1, where F, listed in the last column of Am characteristics are mutually exclusive. One 1 Table I, is based on the slopes of the or two stars, originally classified as metallic-line ( Δ My , Δ [cj ) correlations discussed above. stars have subsequently been found to be variables and a reexamination of the spectrum has This procedure is applied to the young disk suggested they are normal stars (e.g., Breger (but not Hyades group) stars with large and ac- 1970). The conflict, at least for the stars in the curate trigonometric parallaxes, listed in Table temperature range discussed here, may be only V. The first two stars in Table V are the only a matter of nomenclature because several sub- members of the Ursa Major cluster that are groups of metallic-line stars appear to be present in the temperature range discussed here and (Conti 1970) and the divergent values of [m\] are without known companions. The parallaxes are not characteristic of all subgroups. for these cluster stars are those derived from the convergent point of the cluster motion IV. Young Disk Stars with (Eggen 1965b). The values of Δ[7η1] and Slight Metal Deficiency A[ci], together with the trigonometric and The Hyades are unique in the young disk photometric luminosities of the stars in Table V population in that the metal abundance is two or are listed in Table VI. These stars cover nearly three times greater than the solar value. Most of the whole range of departures from the main se- the other young disk stars have nearly solar quence and values of [mj expected in the young abundance and it is therefore necessary to look disk population of the temperature range dis- for any resulting modifications of the luminosity cussed. The rms difference between the trigo- calibration, discussed in the previous sections. It nometric and photometric luminosities, for a has already been noted that the constant term in single star, is (7^25, of which perhaps 0^15 or the ( Δ My , Δ[^ι] ) relation may arise from the 0^2 is caused by the inaccuracies of the photo- fact that the basic (/3, [cj ) relation is based on metric method. field stars which show a mean Δ[7η1], with Crawford and Barnes (1969) found that the respect to the Hyades, near +10. The implica- unevolved main-sequence stars (β < 2.70) in the tion is that the values of [ci] are also affected by Coma Berenices cluster departed from the metal abundance to the extent that A[ci] l, re- (β, rrii) relation for the Hyades stars by ferred to the Hyades, is A[ci] +2Δ[?η1], Aci = —24, and from the (β,ηΐι) relation for which is, by definition (§ I) &[u—b] (cf.. Hyades stars they found a mean value of

TABLE V Young Disk Parallax Stars Name Ve B-V U-B b-y [mi] [Ci] N,N n(tr) 37 U Ma 16 228 200 528 716 3,S 0 0366* HR 4876 85 +0.48 -0.06 318 216 302 641 2,S 0 0385* HR 799 13 +0.49 0.00 326 224 308 625 J,S 0 077 (wt.42) HR 2047 40 +0.60 +0.07 380 261 231 599 8,S 0.101 (wt. 30 ) HR 2943 36 +0.42 +0.02 272 216 478 671 jc^s .283 (wt.75 ) HR 3079 01 +0. 44 -0.06 309 244 324 647 C,2 .067 (wt. 19 ) HR 5235 2.68 +0.58 +0.20 378 274 398 627 J,S .102 (wt. 35 ) HR 7377 3.36 + 0.32 +0.04 210 203 671 739 JC,S .067 (wt.52 ) HR 8430 3.76 + 0.44 -0.03 296 212 387 670 J,S .074 (wt. 44)

* U Ma Cluster (Eggen 1965b) with +0^3 derived from the cluster modulus of 4.5 (e.g., Eggen 1950; Crawford and Barnes 1969). TABLE VI The Sirius group (e.g., Eggen 1960), which Comparison Between Trigonometric and also contains the Ursa Major cluster (e.g., Eggen Photometric Luminosities of Stars in Table V 1965fc), consists of stars with space motions that make the group essentially isoperiodic with the My Name A[mi] a[ci] O C O-C sun (V = 0 km/sec) and with 17-velocities between — 10 and —20 km/sec. These stars may 37 U Ma + 15 -29 + 3¾ + 2^85 + 0^15 be members of a much larger "solar" group (with HR 4 86 7 + 20 -31 + 3.8 + 3. 75 + 0.05 HR 799 + 27 -40 + 3.55 + 3.7 -0.15 U between +5 and —25 km/sec), but for the HR 2047 + 22 -14 + 4.4 + 4.0, + 0 . 4 present purpose only the more restricted group HR 2943 + 4 + 68 +2.6 +2 . 65 -0 .05 HR 3079 -12 -24 + 4. 15 + 4.4 -0.25 will be considered here. The members are listed HR 5235 -15 + 98 +2.7 + 3.1 -0.4 HR 7377 + 14 + 49 + 2 . 5 + 2. 15 + 0.35 in Table VU, which is similar in form to Table HR 8430 -19 + 3.1 + 3. 45 -0.35 II except that the sixth column contains the values of A[c!] 1 and the resulting luminosities. Am! =+14 for the cluster, although the My, derived from the precepts discussed above. {b — y,ß) and, therefore, also the {B—V,ß) Several group members are not included here relations for the two clusters are identical. Be- because of close, unequal companions that dis- cause the Coma stars are unreddened, we can tort the photometric parameters. The stars are equate Aci and Am! to A[c!] and A[m!] shown in the ( [mj ,)3) plane of Figure 5 and the and, applying the precepts discussed above, the (My , B—V) plane of Figure 6. The continuous values of A [m!] and A[c!] essentially cancel curve in Figure 5 represents the mean relation one another leaving A[c!] 1 the same as for the for Hyades stars (Table I) and the broken curve Hyades stars. Therefore the mean of the photo- is displaced by A[m!] = +15. The two Ursa metric luminosities for the unevolved cluster Major cluster members in Table V are shown as stars will give a cluster modulus identical with filled circles in Figures 5 and 6. One star, that derived by fitting the (V, ß— V) diagram to HR3757, has a large, negative value of [mj that of the Hyades. The only two stars in the relative to the other group members and as the Coma Berenices cluster, and in the temperature luminosity is My = +it should be con- range discussed here, that appreciably depart sidered a possible variable, although Danziger from the main sequence are 14 Com, a shell star and Dickens (1967) found it constant over the (for this reason the Ci index is probably unreli- 1/2-hour interval that they monitored its light. able for luminosity determination), and 12 Com, The other group members brighter than My = m a spectroscopic binary. If we ignore the faint + 2 are HR 7101, which would repay examina- spectroscopic companion to 12 Com the photo- tion for variability, and HR 7928, which is the metric results by Crawford and Barnes give known, ultrashort-period (0^14) cepheid δ A[m!] = +24, A[c!] = +205, at )3 = 2.700, Delphini and is a spectroscopic bináry with so A[C!] 1 = +273 and My = +0^6, compared nearly equal components.

TABLE VII Members of the Sirius Group

HP Ve B-V U-B N,N A[ci]] U V w HR b-y [mi] [ci] My dU dV dW Sp. (km/sec) (0V001) 11171A 4.66 +0^04 JC,7 -17 +2 - 5 -152 - 0.9 531 207 225 608 2.738 +2.95 - 8 +1 - 3 - 89 F2 IV Β 6.76 +0.62 +0.125 2,- 72905 5.6 (+0.61) -,s + 15 -11 + 1 -11 - 23 -12.0 3391 390 276 204 2.596 + 4.7 - 1 +4 - 2 + 85 GO V 81937 3.67 +0.33 +0.10 J,S + 125 -15 0 + 1 + 110 - 9.5 3757 211 218 710 2.733 + 1.95 - 4 +1 + 3 + 24 F0 V 105211 4.14 +0.35 +0.01 C,5 + 71 -14 -1 - 8 + 39 + 9.0 4616 218 201 592 2.720 +2.4 - 2 + 1 - 1 - 38 F0 III 109799 5.42 +0.335 +0.025 2,2 + 113 -20 0 -14 + 76 - 0.9 4803 221 206 594 2.703 +2.05 - 5 0 - 3 - 90 F2 V 134083 4.93 +0.43 -0.02 J,S + 32 -19 -1 -17 + 181 - 7.3 5634 285 216 392 2.664 + 3.4 -10 0 - 5 -170 F5 V 143584 5.8 (+0.28) r S + 77 -12 0 + 4 + 9 + 4.0 5964 188 207 693 2.757 +2.25 - 3 -1 0 - 54 F0 IV

174589 6.03 +0.30 +0.06 CfS + 192 -14 0 - 5 0 + 11.8 7101 178 210 798 2.747 + 1.35 0 -1 - 1 - 22 F2 III 197461AB 4.44 +0.32 +0.10 J,S + 256 -19 -1 - 5 - 25 + 8.0 7928 190 197 816 2.738 +0.8 - 2 -1 0 - 44 A7 III

272 β 2-66

Fig. 5 — The Sirius group members (Table VII) in the ([mi] ,j3) plane. The continuous curve represents the + 0-3 B-V +0-5 relation for Hyades cluster stars and the broken curve represents that relation shifted by —15 in [mi]. The Fig. 6 — The Sirius group members in the {My , B—V) filled circles represent members of the Ursa Major plane. The filled circles represent members of the Ursa cluster. Major cluster.

V. Old Disk Population of the bluest member of the Wolf 630 group, is The distribution of the old disk population shown in Figure 8 where the continuous curve stars in the temperature range considered here represents the Hyades cluster stars (Table I). differs considerably from that of the young disk The plus signs and crosses represent the highly population in that most of the objects will be evolved subgiants (My < +3^1, B—V> -1-0^57 near the turn-off point from the main sequence, in Fig. 7) in the ζ Herculis and Wolf 630 groups, near (B—V) = +0^6, where the scale of the )8 in- respectively. For stars redder than about dex collapses. Also, as will be discussed below, (h — y) = 280 there is an obviously systematic the values of β near 2.60 show the effects of the departure from the relation for Hyades stars with luminosity difference between the main-se- the later-type subgiants clearly separated from quence, and near-main-sequence, stars and the the main-sequence stars. Some of the dispersion objects populating the subgiant sequence. in the relation for the near main-sequence stars Therefore in discussing the old disk stars the β is probably also caused by the dispersion in index has been replaced by {h—y). The values luminosity of these evolving stars. The same of [ci] and [mj for age-zero main-sequence stars are shown in the {b—y,B—V) plane of stars (Table I) are listed in Table VIII as a Figure 9 where the straight line represents the function of (h—y). The members of the Wolf 630 relation for Hyades main-sequence stars. Here the mean displacement for stars with (B—V) = + 0^45 to +0^55 is δ(β-V) = +0^03 to +0^)4. TABLE VIII The UBV photometry of these stars shows Photometric Parameters for Age-Zero values of Δ((7—B) = +0^065 and +0^45 for Main Sequence Wolf 630 and ζ Herculis group members, Α-Ζ Main Seq. respectively (Eggen 1971) or Δ(Β—V) = h-y [Ci] [mi] [u-h] Mv Η-0^05 and +0^04 if we interpret the ultraviolet excess as an abundance effect. It appears 210 590 216 1032 + 3¾ that the abundance effect in (h — y) is only about 220 560 215 990 + 3.05 one-half that in (B—V). The distribution of 230 537 215 962 + 3.1 stars in Figure 9 indicates that most of the dis- 240 510 215 940 + 3 250 482 216 914 + 3 persion in Figure 8 arises from the β index and 260 457 217 891 + 3 therefore (h — y) will be used as the temperature 270 434 218 870 + 3 parameter in determining Δ[θι], Δ [mj, and 280 411 220 851 + 3.65 Mv(AZMS) for old disk population stars in the 290 392 222 836 + 3.8 300 372 226 824 + 3.9 range (h — y) = 260 to 400 (Table VIII). There 310 353 230 813 + 4.0 are very few of the earlier type, "blue stragglers" 320 336 234 804 + 4.1 in the present sample, and they can be more con- 330 321 240 801 + 4.2 veniently discussed in a later paper concerning 340 306 246 798 + 4. 35 350 293 252 797 + 4. 45 the A-type stars. 360 280 260 800 + 4.55 The (h—y, [mi]) relation of Table VIII is 370 269 268 805 + 4.65 shown as a continuous curve in Figure 10 and a 380 258 277 812 + 4. 75 mean value of [mj = +25 for the group stars 390 247 286 819 + 4.9 Δ 400 237 296 829 +5.05 is represented by the broken curve. With the exception of HR 1257 {[mi] = 256) in the Wolf 630 group, the dispersion in [mj for the group and ζ Herculis groups, in the temperature range Δ considered here, are listed in Tables IX and X, members is satisfactorily small. respectively, where the data are arranged as in The old disk group stars, with (h—y) between Table II. The (My, B—V) relation for these 260 and 400 are listed in Table XI together with 1 stars is shown in Figure 7, which also contains values of Δ [cj , derived with the precepts dis- some members of the old disk cluster M 67 (Eg- cussed above, and the values of ( ΔΜν)ο repre- gen and Sandage 1964). The correlation between sent the deviations from the age-zero main se- β and (h — y) for these stars, with the exception quence in Table VIII. The stars in Table XI are

TABLE IX Members of the Wolf 630 Groups

HP Ve Β— V U-B N,N U V W m— M HR b-y [mi] [Cj dU dV dW μ δ Sp. AR (km/sec) (ο','οοΐ) 2454 6^04 -0^08 2 f 4 -13 -33 -15 + 32 + 9.9 3?00 107 295 195 369 2.660 - 3 - 7 - 6 -192 F2 V 0.8 4307 6.11 +0.585 +0.05 2,2 -28 -33 + 3 - 32 -12.8 3.11 203 385 267 265 2.635 - 6 - 7 - 2 -202 dF8 0.30 6479 6.32 +0.385 -0.025 2/2 -12 -33 -12 + 25 - 7.4 3.92 313 257 186 459 2.690 - 1 - 5 - 3 -116 dF4 0.8 6480 7.23 +0.485 -0.04 2/2 314 336 (187): 325 2.627 dF5 7908 7.27 +0.28 +0.10 2/2 -14 -33 -13 + 10 + 11.1 6.15 182 168 575 2.718 - 1 - 2 0 - 55 A7 III 0.8 25621 5.35 +0.50 +0.02 C/2 -14 -33 + 17 + 150 -17.8 2.90 1257 334 256 46 4 2.615 0 - 9 + 2 -124 F6 IV 0.11 33021 6.16 +0.62 +0.08 C/S -38 -33 -24 - 3 -23.8 2.13 1662 396 256 267 2.585: - 6 -14 - 9 -378 dG2 0.14 45504 6.4 (+0.52) -,s -13 -33 +22 +119 - 6.8 4.01 2339 342 230 321 2.609 - 1 - 5 + 4 - 67 F5 0.20 49095 5.92 +0.48 -0.04 2/2 -32 -33 -73 -219 + 32.0 3.20 2500 329 203 319 2.612 -11 - 1 -15 -326 dF6 6.3 71148 6.36 +0.63 +0.11 3 / S -22 -33 -23 - 22 -33. 8 1.30 3309 394 285 239 2.583 + 3 -17 - 2 -363 dG4 0.00 87998 7.26 + 0.62 + 0.04 3/2 -10 -33 -30 -136 + 12.1 2.05 GC13929 398 258 255 2.581 - 4 - 9 -14 -336 G2 V 1.0 124850 4.08 +0.515 +0.025 JC/S -24 -33 -13 - 9 -11.5 1.55 5338 341 225 380 2.622 - 8 -14 -11 -429 F7 IV 0.16 126660 4.06 +0.50 + 0.01 J,S -10 -33 + 7 -238 -10.9 0.95 5404 334 216 341 2.644 - 7 -18 + 11 -401 F7 V 0.28 130989 6.50 + 0.46 -0.04 C/2 -26 -33 - 17 + 25.8 3.80 GC19985 316 202 405 2.632 - 1 - 4 -125 dF5 0.6 193307 6.28 +0.55 -0.02 2/2 -30 -33 + 19 -352 + 18.0 1.73 7766 365 233 251 2.619 - 7 -14 + 13 -239 G2 V 0.11 200790 5.96 +0.54 +0 .02 3 / S -14 -33 + 18 - 94 -22.0 3.02 8077 350 233 351 2.625 - 6 - 4 0 -126 F8 1.8 215243 6.45 +0.46 -0.02 2 / S -24 -33 -30 + 7 - 2.0 4.13 8653 318 212 368 2.642 - 4 - 5 - 5 -158 F5 1.6 215648 4.19 + 0.50 -0.02 J/S - 4 -33 -29 +226 + 5.3 1.15 8665 330 207 341 2.626 - 3 -17 -19 -492 F7 V 0.45 217096 6.10 +0.58 +0.05 1/2 -20 -33 -16 - 3 +21.4 4.24 8732 372 253 416 2.634 - 2 - 5 0 -108 G3 IV 0.10 223029 7.97 +0.53 +0.0 3 3/2 -17 -33 +18 15 -32.5 5.00 GC32987 355 249 315 2.581 - 2 - 2 - 1 49 dF6 3.30

TABLE Χ Members of the ζ Herculis Group

HP Ve B-V υ-Β Ν,Ν U V W m— M HR b-y [mi] [Cx] dU dV dW Sp. ΔΚ (km/sec) (O'.'OOI) 25945 5^60 +0^33 -0^02 2,5 +6 3 -47 -15 + 197 +63.5 3^30 1275 220 190 671 2.723 + 7 - 4 + 7 + 97 F0 V 1.4 34411 4.72 +0.61 +0.12 4 , S + 77 -47 + 5 + 460 +65.7 0.98 1729 389 276 285 2.598 + 8 -39 + 2 -658 GO V 0.05 71030 6.10 +0.45 -0.02 3,S + 48 -47 -40 -191 + 37.5 3.84 3299 286 197 432 2.660 + 3 - 5 -10 -157 dF4 0.7 88742 6.35 +0.59 +0.09 1,2 + 45 -47 -369 + 41.8 2.28 4103 372 269 274 2.593 + 16 - 2 + 55 G1 V 4.2 88218 6.12 +0 . 5 8 +0.16 C, 2 + 42 -47 -17 -435 + 40.9 2.00 3992 384 250 256 2.580 + 17 - 3 -11 + 6 dF 9 2.9 89995 6.54 +0.44 -0.06 5,S +56 -47 -21 -240 +29.8 3.85 4079 302 190 394 2.634 + 8 - 5 - 7 - 78 F2 1.1 96700 6.50 +0.60 +0.09 2,2 +62 -47 -46 -515 + 12.4 2.77 4328 385 245 229 2.581 + 18 -10 -15 -141 G2 V 0.9 120066 6.32 +0.62 +0.14 8,3 +54 -47 -19 -512 -31.1 2.20 5183 393 256 308 2.600 + 15 -19 + 3 -111 dG2 0.08 150680* 2.81 +0.65 +0.21 J, S +53 -47 -26 -472 -69.9 0.00 6212 415 282 325 2.613 +21 - 4 + 19 + 391 GO IV 1.4 156846 6.50 +0.5 8 +0.10 2,2 +66 -47 + 2 -147 -69.2 3.48 6441 368 266 378 2.628 0 - 8 + 3 -112 G3 IV 0.00 158170 6.36 +0.58 +0.15 C, 2 +50 -47 -13 - 83 -64.0 3.50 6504 381 253 528 2.654 - 2 - 5 0 -130 F8 0.45 196378 5.10 +0.53 -0.02 2,2 +65 -47 + 314 -31.5 1.90 7875 350 219 284 2.622 + 18 -24 -568 F8 V 0.15 211415 5.33 +0.61 +0.06 2,2 + 32 -47 + 8 + 428 -13.6 0.91 8501 385 261 207 2.584 + 16 -34 - 2 -660 G1 V 0.07

♦Note to Table X HR 6212 ζ Her, companion 3Φ5 fainter. The 42 bright stars of the old disk population divided into three temperature groups, (b — y) = in Table XII are listed in Gliese's (1969) catalog 260-300, 300-360, and 360-400. Values of of nearby stars. The columns of Table XII con- ( AMv)c' derived from A[ci]1 and the ap- tain the following information: propriate value of F, for the observed value of 1. HD/HR/spectral type. (b—y) (Table I) match the observed values of 2. VeIB-VIU-B. Δ My very well in the range of (b — y) = 3. b-yl[mi]l[ci]. 260-360, with an rms deviation for a single star of 4. ρΙΝ,Ν source of broad- and intermediate- 0^25. With one or two exceptions (HR 6504 and, band results, respectively (see §I)/A[m1] perhaps, HR 7766) reasonably accurate values of (Table VIII). Δ My can apparently be computed for stars as 5. Aid] (Table VIII) + 2 Δ [mj red as {b—y) = 390. However, for redder stars + 20lô{U— B) (units of 0^01), referred to the method breaks down. the Hyades and corrected for the gravity

Fig. 7 —The {Mv,B-V) relation for some old disk population stars.

+ 0-3 B-V +0-4 +0-5 +0-6

oW630 χ G-type sg •CHer + G-type sg

Fig. 8 — Correlation between β and (b — y) for members of the Wolf 630 and ζ Herculis group members. Highly evolved subgiants are shown as crosses and plus signs. +0-4 B-V +0-6 The continuous curve represents the Hyades cluster stars (Table I). Fig. 9 — Correlation between (b — y) and (B—V) for the stars in Figure 8. The coding is the same as that in effect as discussed below / My, computed Figure 8. The straight line represents the relation for 1 from AMy = FA[ci] and Mv (AZMS, main-sequence stars of the Hyades cluster. Table VIII). 6. UIVIW, the vectors of the space motion. the General Catalogue of Trigonometric 7. Photometric parallax from My (column 5) / Stellar Parallaxes. individual, high weight trigonometric The (My, B—V) diagram for these stars is parallaxes in units of CK'OOl, with the usual shown in Figure 11, where the six stars with observatory abbreviations and, in paren- Δ [mi] > +40 are indicated by filled circles. theses, the weight based on the precepts in The accuracy of the individual values of My can

200 0-12 ["ψ ^ptm 220

008 240

260 0-04 280 0 04 TTtn 008 0-12

Fig. 10 — The correlation between [mi] and (b — y) for Fig. 12 — The correlation between photometric and the members of the Wolf 630 and ζ Herculis groups. The trigonometric parallaxes in Table XIL coding is that used in Figure 8. The continuous curve represents the relation for main-sequence members of the Hyades cluster. The broken curve represents that relation shifted by —25 in [mj].

Fig. 11—The parallax stars (Table XII) in the (My , B—V) plane. Fig. 13 — Correlation between (U—B), corrected for the gravity effect, and Δ [mi] for the parallax stars in Table XII. Filled circles represent stars more than 0Φ75 above be judged in Figure 12, where the photometric the main sequence. parallaxes are correlated with the mean Cape and Yale trigonometric values (open circles) and from common proper-motion pairs. The values the Allegheny results (filled circles). When an of δ {Ό—Β) are considerably more sensitive to alternative to the Allegheny result is available it metal abundance than the values of A[m1] but, is indicated by the tip of an arrow. as already mentioned, the presence of the gravity The values of 0{U—B) in Table XII are re- effect in the former limits their use. However, ferred to the Hyades main-sequence stars cor- with luminosities computed from the inter- rected for the gravity effect. This effect was mediate-band results, the known gravity effects previously calibrated (Eggen 1966, Table II) can be removed from 8{U—B) and the values

TABLE XI The Photometric Parameters and Luminosities of Wolf 630 and ζ Herculis Group Members aMv HR b-y A[Cl]> O o-c

b-y = 260-300

313 257 + 76 +0^95 +0^75 +0¾ W 630 3299 286 +100 + 1.5 + 1.1 +0.4 ζ Her 107 295 + 65 +0.8 +0.7 +0.1 W 630 b-y = 300-360

4079 302 +120 + 1.2 +1.4 -0.2 ζ Her GC19985 316 + 142 +1.35 +1.75 -0.4 W 630 8653 318 + 91 +1.8 +1.15 +0.65 W 630 2500 329 + 88 + 1.5 + 1.2 +0.3 W 630 8665 330 +106 +1.15 +1.4 -0.25 W 630 1257 334 +141 +1.8 +1.95 -0.15 W 630 5404 334 + 98 + 1.15 +1.35 -0.2 W 630 5338 341 +139 +1.8 +2.0 -0.2 W 630 2339 342 + 70 +0.95 +1.0 -0.05 W 630 7875 350 + 77 +1.25 +1.2 +0.05 ζ Her 8077 350 +116 + 1.5 + 1.8 -0.3 W 630 GC32987 355 + 63 +1.55 +1.05 +0.5 W 630 b-y = 360-400

7766 365 + 58 + 0.15 + 1.0 (-0.85) W 630 6441 368 + 127 + 1.65 +2.15 -0.5 ζ Her 8732 372 + 193 +2.8 + 3 . 4 -0.6 W 630 4013 373 + 31 +0.6 +0.55 +0.05 ζ Her 6504 381 + 321 + 1.9 (+5.9) ζ Her 3992 384 84 +0.7 + 1.3 -0.6 ζ Her 4328 385 51 +1.1 +0.95 +0.15 ζ Her 203 385 60 +1.85 + 1.15 +0.7 W 630 8501 385 14 +0.4 +0.25 +0.15 ζ Her 1729 389 74 + 1.15 +1.4 -0.25 ζ Her 5183 393 + 150 +0 . 85 ζ Her 3309 394 + 34 +0.1 W 630 1662 396 - 26 + 1.0 W 630 GC13929 398 + 108 -0.2 W 630 listed in Table XII were derived in this way. rotation (e.g., Strömgren 1966 and references The correlation between Δ [mj] and these therein) may appear in a few individual stars, corrected values of δ (U—isthe general shown correlationin Figure is good and indicates that 13 where the filled circles represent stars more the scale of Δ[ίη1] is about one-third that of than iï"75 from the main sequence. Although the d{U-B). effects on the indices of microturbulence and

TABLE XII CU< Old Disk Stars with Trigonometric Parallaxes (1) (2) (3) (4) (6) (7) (1) (2) (4) (5) (6) (7) 142 5.7 4 340 2.639 61 + 66 0:0 345 70958* 5.60 315 2.623 +77 +61 0.032 6 + 0.50 236 2,2 3 - 41 35Y(12) 3297 + 0. 46 197 C,S +11 - 48 53A (2 8) G1 V + 0.02 327 + 10 3.45 - 14 55C(7) dF2 -0.07 331 + 35 +3.1 - 5 36(10) 1581 4.22 371 2.606 - 12 + 62 0.134 82328* 3. 18 314 2.646 +120 + 57 0 .077 77 +0.575 249 JC, 2 + 9 - 4 129(10) 3775 + 0.46 209 J,S + 4 - 34 60A(16) G2 V +0.015 196 + 2.0 + 4. 85 - 39 143C (5) F6 IV +0.0 3 400 +23 + 2.6 - 24 5015 4.80 346 2 .613 + 56 + 7 0 .068 84117 4.90 336 2.609 + 73 + 54 0.047 244 +0.555 255 2,S + 4.5 + 21 6 2M(8) 3862 + 0.52 220 2,2 + 10 - 24 55Y (8) F8 V +0.04 343 -5 + 3.95 + 12 GO V -0.03 317 + 24 + 3.25 + 3 98C (6) 7439* 5.17 290 2.647 + 63 + 36 0.037 91324 4.91 326 2.600 + 140 + 39 0. 049 366 + 0. 41 196 3,S + 8 + 22 38A(16) 4134 + 0.50 197 2,2 + 16 - 29 55Y (10) F5 V -0.07 383 + 26 + 3.1 46 Y ( 16 ) dF7 -0.06 365 + 41 + 2. 35 - 3 2 7 C ( 17 ) 9826 4.09 346 2 .629 + 85 - 30 0.063 91889 5.68 845 2.595 + 115 -110 0.025 458 +0.5 3 239 3,S + 4 - 23 6 4A(2 8) 4158 +0.525 207 5,2 + 9.5 - 55 27Y (12) F8 V +0.06 341 + 11 + 3.1 - 19 5 3M(7) F8 V -0 .005 311 + 42 + 2.7 - 60 43M (6 ) 11443 3.42 316 2 .637 + 153 - 11 0.055 102870 3.60 354 2.628 + 78 - 43 0.085 544 +0.48 213 3,S + 7 - 18 4 8A(16) 4540 +0.555 252 JC,S + 0.5 + 3 9 8A(18) F6 IV + 0.03 438 + 19 + 2. 15 - 9 5 8M(4) F8 V +0.105 341 + 3 + 3.25 + 7 100Y (12) 12235 5. 88 388 2.624 + 116 + 2 0.023 114710 4.26 372 2.609 + 33 + 57 0 .096 582 + 0.61 278 2 , S 0 - 73 30A (2 8) 4983 +0.58 260 J^ + 2 + 13 114A(20) dGl +0.16 333 +6 + 2.7 + 1 36Y(12) GO V +0.08 262 + 10 + 4.15 + 9 120M(7) 19373 4.05 376 2.605 + 67 + 84 0.079 114837 4. 92 324 2.633 + 32 + 55 0.059 937 +0 .60 269 J,S + 2 - 24 79A(20) 4989 +0.48 206 2.2 + 8 + 35 47Y (10) GO V + 0. 11 301 + 4 + 3.55 + 27 84M(8) F8 V -0.06 282 + 30 + 3.75 - 15 47C(18) 20010* 3.86 339 2 .624 + 113 + 45 0.060 125276 5.88 351 2. 596 + 54 + 58 0 .035 963 + 0.53 217 JC,S + 8 + 22 6 8Y ( 12) 5356 + 0. 49 188 2.3 + 16 + 6 52Y (10) F8 IV + 0.02 343 +29 + 2.75 + 33 52C (7) dF 4 -0.12 196 + 65 + 3.6 + 41 32C (7) 20807* 5.23 380 2 .570 - 15 + 66 0 . 090 128020* 6.02 328 2.612 + 55 + 71 0.031 1010 + 0.61 267 2,2 + 14 - 44 9 3C ( 8) 5443 +0.50 208 C, 2 + 8.5 - 22 46Y(12) G1 V 0.00 203 + 10 + 5.0 + 14 75Y (11) F5 -0.04 297 + 31 + 3.45 - 14 40C (7) 22001* 4.70 259 2 .673 + 60 + 57 0.042 128167 4. 47 254 2. 681 + 57 - 3 0 .047 1083 +0. 39 198 C, 5 + 6 - 25 55Y (10) 5447 +0 . 37 181 J,S + 11 + 22 73A(20) F5 V -0.04 457 + 19 + 2.8 0 47 (8) F2 V -0.08 439 + 37 + 2.8 - 7 29M(7) 23754 4.22 276 2 .670 + 43 - 33 0.061 136064 5. 14 350 2.629 + 103 - 68 0.035 1173 +0.425 211 JC, 4 + 2 - 21 6 9M(7) 5691 + 0.54 240 2 , S + 7 - 27 45A(20) F3 V 0.00 437 + 8 + 3.15 - 19 44CY(14) F8 V + 0 .02 352 + 12 + 2.85 - 22 43M(8) 34721* 5 .95 368 2 .565 + 34 + 37 0.041 141004 4.43 375 2.608 + 39 + 50 0.0 82 1747 + 0.58 270 1,2 + 10.5 - 44 59C (6) 5868 +0.60 269 JC, 5 + 3 - 24 83A(16) dGO +0.005 293 + 4.0 + 19 GO V + 0. 10 277 + 3 + 4.0 - 40 9IM (6 ) 43587 5.70 382 2.593 + 29 + 20 0.0525 142373 4.62 380 2.600 + 69 + 43 0.060 2251 +0.605 269 C, 2 + 4.5 + 30 49A(16) 5914 + 0 .57 240 J, 3 + 11 + 14 57A (2 8) dGO +0.09 255 + 10 + 4.3 47Y(10) F9 V 0.00 247 + 30 + 3.5 - 69 46M (10) 48682 5.24 357 2.640 + 54 - 26 0 .048 142860 3. 86 320 2.633 + 69 - 68 0.074 2483 + 0.55 249 , 3,S + 4.5 + 12 75A(20) 5933 + 0.48 211 J,S + 8 - 41 73A (20 ) GO V + 0.05 300 + 9 + 3.65 - 1 49M (8) F6 IV -0.03 339 + 23 + 3.2 - 32 99M (7) 52711 5.93 374 2 .600 + 5 + 16 0.054 173667 4^19 314 2.648 + 139 - 41 0 !! 0 4 5 2643 + 0.60 265 3,S + 7 - 76 56A(16) 7061 + 0.46 206 J,S + 7 0 46A(2 8) G4 V + 0.06 226 + 7 + 4.6 - 9 6 IM(7) F6 V +0.02 421 + 26 + 2.35 - 10 6 IM(8) 60532 4.44 333 2 .595 + 170 + 39 0.032 187013* 5 .00 316 2 .646 + 89 - 45 0 .039 2906 +0.515 218 JC, 2 + 6: - 48 47Y(10) 7534 + 0 . 45 212 3,S + 4 - 10 43A(2 8) F7 IV +0.06 419 + 24 + 1.95 - 3 F5 V 0.00 372 + 20 + 2 . 95 - 28 43S (20) 63077 5.38 376 2 .548 + 38 + 164 0.054 189340 5 . 88 377 2 .617 + 52 - 53 0.038 3018 +0.56 219 2,2 + 18 - 50 5 4Y(12) 7637 + 0.58 262 2,3 + 7 - 38 37A(16) GO V -0.085 172 + 54 + 4.05 6 5C (6 ) GO V + 0 . 04 251 + 21 + 3. 75 + 1 37YC (17) 65907* 5^59 362 2.572 + 24 14 0^051 190406 5 . 80 389 2 .615 + 51 - 56 0.043 3138 +0.58 237 3,1 + 8 24 63Y (12) 7672 +0.060 267 2 , S + 5 - 30 6 3A (2 8) G2 V +0.0 3 242 +25 + 4. 15 42 50C (6) dGl + 0 .08 243 + 18 + 3.95 + 12 30M(7) 68456 4. 75 292 2.652 + 90 22 0.041 203608 4.22 328 2 .612 - 7 + 13 0. 105 3220 +0 . 43 192 C, 5 + 6 14 55Y(10) 8181 + 0.48 183 JC, 2 + 15 + 42 121Y (10) dF7 -0.03 396 + 31 + 2.8 37 47C (18) F 8 V -0.13 195 + 56 + 4.3 95C(7) 69897 5.14 314 2.636 + 55 23 0 .044 214953 6.02 363 2.677 + 132 14 0.031 3262 +0.47 202 J,S + 8 46 6 4A(16) 8635 + 0.53 231 3,2 + 15 51 32C (8) F6 V -0.05 321 + 30 + 3.4 4 60S (8) G1 V + 0.07 327 + 31 + 345 4 82Y(7)

Crawford, D. L., and Barnes, J. V. 1969, A.J. 74, 407. * NOTES TO TABLE XII Crawford, D. L., and Perry, C. L. 1966, A.J. 71, 206. HR 366 Cpm companion, 50"; (V, B—V, U—B) = Crawford, D. L., and Strömgren, Β. 1965, in Vistas in (7.87, +0.78, +0.35). ni Astronomy, vol. 8, A. Beer, ed. (Oxford: Pergamon HR 963 Am = 2 5, Ρ = 150 years. Press), p. 149. HR 1010 HR 1006, Cpm; (V, Β— V, U- B) = (5.49, Crawford, D. L., Barnes, J. V., and Golson, J. C. 1970, + 0.65, +0.055) and {b y, [mi], [ογ], β) = A.J. 75, 624. (411, 397, 235, 2,551). The trigonometric Crawford, D. L., Barnes, J. V., Faure, Β. Z., Golson, parallaxes are the means for the two com- J. C., and Perry, C. L. 1966, A.J. 71, 709. ponents. Danziger, I. J., and Dickens, R. J. 1967, Ap. J. 149, 55. HR 1083 Cpm companion, 54"; (V, B—V, U—B) = Eggen, O. J. 1950, Αρ. J. ill, 415. (10.78, + 1.445, + 1.19) and (fí, R-I) = 1960, M.N.fí.A.S. 120,563. (9.84, +0.765). 1964, AJ. 69, 570. HR 1747 (μ^,μδ) = (+0'.'382, +07058), ρ = +40.0 1965a, Annual Rev. of Astr. and Astrophysics 3, 235. km/sec. 1965¿>, The Observatory 85, 105. HR 3138 Cpm companion, 48"; {V,B~V,U-B) = 1966, Roy. Obs. Bull. No. 120. (9.38, +1.35, +1.09). 1968, Roy. Obs. Bull. No. 137. HR 3297 Probably a member of the ζ Herculis group but 1970a, Ap.J. 161, 159. too little dependence of the V-velocity on the 1970¿>, Vistas in Astronomy, vol. 12, A. Beer, ed. distance to be included in Table X. (Oxford: Pergamon Press), p. 367. HR 3775 A member of the e Indi group. = 1971, Pub. A.S.P. 83, 271. HR 5443 (μα>μδ') (—0"350, -0^274), Ρ = -30.0 Eggen, O. J., and Sandage, A. R. 1959, M.N.fí.A.S. 119, km/sec. 278. HR 7534 Cpm companion, 26"; (V, Β— V, JJ— B) = 1964, Αρ. J. 140, 130. (8.54, +1.03, +0.93): also ADS 12889, Cpm; diese, W. 1969, Veröff, Astr. Rech-Inst. Heidelberp, (V, B-V, U-B) = (8.39, +0.98, +0.78), No. 22. Am = 0, Johnson, H. L. 1952, Ap. J. 116, 640. Johnson, H. L., and Knuckles, C. F. 1955, Ap. J. 122, 209. REFERENCES Johnson. H. L., Mitchell, R. E., Iriarte, B., and Wis- Breger, M. 1969, Ap. J. Suppl. 19, 29 (No. 169). niewski, W. Z. 1966, Comm. Lunar and Planetary 1970, Ap.}. 162, 597. Lab. 4, 99. Conti, P. S. 1970, Pub. A.S.P. 82, 781. Perry, C. L. 1969, A.J. 74, 705. Cousins, A. W. J. 1967, Unnumbered Mimeogram, Cape Strömgren, Β. 1963, Quart. J.R.A.S. 4, 8. Observatory. 1966, Annual Rev. of Astr. and Astrophysics 4, 423.