2006MNRAS.372.1407C

Query : 2006MNRAS.372.1407C

2006MNRAS.372.1407C - Mon. Not. R. Astron. Soc., 372, 1407-1424 (2006/November-1)

A census of the Wolf-Rayet content in Westerlund 1 from near-infrared imaging and spectroscopy.

CROWTHER P.A., HADFIELD L.J., CLARK J.S., NEGUERUELA I. and VACCA W.D.

Abstract (from CDS):

New Technology Telescope (NTT)/Son of Isaac (SOFI) imaging and spectroscopy of the Wolf-Rayet population in the massive cluster Westerlund 1 are presented. Narrow-band near-infrared (IR) imaging together with follow up spectroscopy reveals four new Wolf-Rayet stars, of which three were independently identified recently by Groh et al., bringing the confirmed Wolf-Rayet content to 24 (23 excluding source S) - representing 8 per cent of the known Galactic Wolf-Rayet population - comprising eight WC stars and 16 (15) WN stars. Revised coordinates and near-IR photometry are presented, whilst a quantitative near-IR spectral classification scheme for Wolf-Rayet stars is presented and applied to members of Westerlund 1. Late subtypes are dominant, with no subtypes earlier than WN5 or WC8 for the nitrogen and carbon sequences, respectively. A qualitative inspection of the WN stars suggests that most (∼75 per cent) are highly H deficient. The Wolf-Rayet binary fraction is high (≥62 per cent), on the basis of dust emission from WC stars, in addition to a significant WN binary fraction from hard X-ray detections according to Clark et al. We exploit the large WN population of Westerlund 1 to reassess its distance (∼5.0kpc) and extinction (AKS∼ 0.96mag), such that it is located at the edge of the Galactic bar, with an oxygen metallicity ∼60 per cent higher than Orion. The observed ratio of WR stars to red and yellow hypergiants, N(WR)/N(RSG + YHG) ∼3, favours an age of ∼4.5-5.0Myr, with individual Wolf-Rayet stars descended from progenitors of initial mass ∼40-55M☉. Qualitative estimates of current masses for non-dusty, H-free WR stars are presented, revealing 10-18M☉, such that ∼75 per cent of the initial stellar mass has been removed via stellar winds or close binary evolution. We present a revision to the cluster turn-off mass for other Milky Way clusters in which Wolf-Rayet stars are known, based upon the latest temperature calibration for OB stars. Finally, comparisons between the observed WR population and subtype distribution in Westerlund 1 and instantaneous burst evolutionary synthesis models are presented.

Abstract Copyright: 2006 The Authors. Journal compilation © 2006 RAS

Journal keyword(s): stars: Wolf-Rayet - open clusters and associations: individual: Westerlund 1

Errata: erratum vol. 385, p. 544 (2008)

Simbad objects: 133

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Number of rows : 133
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 HD 4004 WR* 00 43 28.3971737448 +64 45 35.384652468 10.28 10.718 10.138     WN4-s 205 0
2 HD 269582 WR* 05 27 52.6621673400 -68 59 08.488879836 12.206 10.818 11.093 12.70 11.234 WN10h 117 0
3 HD 269687 WR* 05 31 25.5247745448 -69 05 38.556251700 10.86 11.78 11.87 12.05   WN11h 122 0
4 HD 50896 WR* 06 54 13.0439608392 -23 55 42.023319852 5.74 6.63 6.91 7.74   WN4b 794 0
5 CD-28 5180 ** 07 57 58.5439081776 -28 35 29.306943276 10.46 11.19 10.87 10.90   OB 20 0
6 Cl Ruprecht 44 OpC 07 58 49.6 -28 33 44   7.66 7.2     ~ 65 0
7 HD 65865 WR* 07 59 46.2451717872 -28 44 03.085045476 10.62 11.20 10.90 11.16   WN5h 108 0
8 CD-28 5257 EB* 08 00 03.2548743144 -28 50 25.866686544 10.89 11.62 11.35 11.44   OB- 24 0
9 * gam02 Vel WR* 08 09 31.95013 -47 20 11.7108 0.64 1.58 1.83 1.85 2.00 WC8+O7.5III-V 951 0
10 CD-45 4447 * 08 43 24.1537949616 -46 08 28.658569200 10.76 11.26 10.77 11.02   O7.5V 20 0
11 CPD-45 2920 EB* 08 43 49.8047993256 -46 07 08.757379416 10.6 11.36 10.99 10.91   O6.5V(n)((f)) 39 1
12 CD-45 4472 * 08 44 25.0614061680 -45 53 34.556812908 11.45 11.90 11.29 11.21   OB 15 0
13 Cl Bochum 7 OpC 08 44 28.2 -45 55 19   6.94 6.8     ~ 52 0
14 CD-45 4482 WR* 08 44 47.2901340000 -45 58 55.417387548 10.95 11.29 10.74 10.58   WN8h+? 108 0
15 HD 76536 WR* 08 54 59.1670918944 -47 35 32.662167792 9.04 9.13 8.80 9.52   WC 129 0
16 HD 86161 WR* 09 54 52.9033957968 -57 43 38.274644604 7.94 8.65 8.36 8.93   WN8h 230 0
17 V* V712 Car EB* 10 23 58.0126366512 -57 45 48.937268268 15.466 15.473 13.5 12.6   O3If*/WN6+O3If*/WN6 176 0
18 Cl Westerlund 2 OpC 10 23 58.1 -57 45 49           ~ 400 0
19 Cl* Westerlund 2 MSP 151 * 10 24 00.4800478179 -57 45 23.965667265 15.792 16.031 14.546 13.83 12.414 O4V 14 0
20 Cl* Westerlund 2 MSP 157 Y*? 10 24 00.73608 -57 45 25.3908   15.50 14.14 13.009   O6.5V 12 0
21 Cl* Westerlund 2 MSP 167 * 10 24 02.0625463104 -57 45 27.966989664 16.001 16.117 14.453   12.121 O8V 18 0
22 Cl Westerlund 2 5 * 10 24 02.4404730984 -57 44 36.147162768 14.149 14.514 13.155 12.2   O5/5.5V/III(f) 26 0
23 Ass Car OB 1 As* 10 38 -59.0           ~ 172 0
24 HD 93131 WR* 10 43 52.2579213120 -60 07 04.019676456 5.52 6.43 6.48 7.46   WN6ha-w 309 0
25 Cl Collinder 228 OpC 10 44 00 -60 05.2           ~ 211 0
26 V* V661 Car SB* 10 44 00.3711575208 -59 52 27.521778900 7.60 8.31 8.04 8.75   O6.5III(f) 148 0
27 HD 93162 WR* 10 44 10.3890266112 -59 43 11.106500520 7.90 8.55 8.80 8.66   O2.5If*/WN6+OB 374 0
28 HD 93206 * 10 44 22.9085235888 -59 59 35.970489960 5.53 6.37 6.24 7.42   O9.7Ibn 223 0
29 HD 93204 * 10 44 32.3390794992 -59 44 31.020804780 7.63 8.52 8.42 8.20 7.92 O5.5V((f)) 200 0
30 V* V560 Car SB* 10 44 33.7393258944 -59 44 15.434446956 6.89 7.80 7.75 7.56 7.46 O3.5V((f))+O8V 314 0
31 HD 93250 ** 10 44 45.0275085072 -59 33 54.680974848 6.73 8.12 7.50 8.38   O4III(fc) 334 0
32 Cl Trumpler 16 OpC 10 45 01.9 -59 42 00           ~ 510 0
33 HD 303308 ** 10 45 05.9147911152 -59 40 05.925360036 7.45 8.30 8.17 7.92 7.75 O4.5V((fc)) 314 0
34 HD 305525 * 10 46 05.7017733864 -59 50 49.380764388 10.26 10.68 10.00 10.03   O5.5V(n)((f))z 48 0
35 HD 93632 * 10 47 12.6337916088 -60 05 50.814051396 7.89 8.69 9.10 9.04   O5Ifvar 97 0
36 HD 96548 WR* 11 06 17.2032351624 -65 30 35.241182028 7.10 7.80 7.70 8.49   WN8h 427 0
37 NGC 3603 OpC 11 14 57.9 -61 14 32           ~ 1136 1
38 Cl* NGC 3603 MDS 42 * 11 15 07.06 -61 15 39.3   13.98 12.86     O3III 14 0
39 Cl* NGC 3603 BLW A2 * 11 15 07.31 -61 15 38.8   13.51 12.53     O3V 20 0
40 Cl* NGC 3603 BLW A1 WR* 11 15 07.31 -61 15 38.4   12.32 11.18     WN6h 73 0
41 Cl* NGC 3603 BLW A3 * 11 15 07.35 -61 15 38.4   14.07 12.95     O3III(f*) 21 0
42 Cl* NGC 3603 MDS B WR* 11 15 07.4080492426 -61 15 38.613880686   12.34 11.33     WN6h 44 0
43 Cl* NGC 3603 MDS C WR* 11 15 07.5851367565 -61 15 38.027795970   12.94 11.89     WN6h 49 0
44 NGC 3603 47 * 11 15 09.3526936584 -61 16 02.077865112 13.49 13.71 12.67     O4IV(f) 23 0
45 HD 104994 WR* 12 05 18.7204232424 -62 03 10.140656832 9.95 10.94 10.93 11.03   WN3p-w 170 0
46 M 83 SBG 13 37 00.91920 -29 51 56.7400 8.85 8.11 7.52 7.21   ~ 2778 2
47 HD 134877 WR* 15 14 57.7186057272 -59 50 30.215432688 12.13 12.19 11.34 11.08   WN8(h) 112 0
48 Cl Pismis 20 2 * 15 15 22.0691635920 -59 03 45.526077036   13.46 12.48     O8.5I 10 0
49 Cl Pismis 20 OpC 15 15 23.5 -59 04 23   8.69 7.8     ~ 103 0
50 HD 134959 s*b 15 15 24.0871041696 -59 04 29.296677756 9.05 9.14 8.10 8.642   B2Ia 83 0
51 MR 55 WR* 15 15 32.6272277376 -59 02 30.695283672 12.46 12.56 11.84 11.63   WN6-w 72 0
52 HD 147419 WR* 16 24 26.2279587024 -51 32 06.061114140   11.46 10.50 10.74   WN6-s 114 0
53 WR 75c WR* 16 34 03.5829153744 -43 40 24.818581704         13.026 WC9 8 0
54 2MASS J16464447-4550044 LP? 16 46 44.4750588408 -45 50 04.462684260           ~ 2 0
55 2MASS J16464503-4548311 NIR 16 46 45.0285117624 -45 48 31.219274592           ~ 1 0
56 Cl Westerlund 1 OpC 16 47 02.4 -45 51 07           ~ 655 1
57 Cl* Westerlund 1 W 9 WR* 16 47 04.1419806984 -45 50 31.311670632   21.8 17.47 14.47 11.74 sgB[e] 56 0
58 Cl* Westerlund 1 W 243 s*b 16 47 07.5040736160 -45 52 29.123491188   19.873 15.730     LBV 67 0
59 Cl* Westerlund 1 W 263 * 16 47 11.79 -45 48 36.1           M5III~ 7 0
60 HD 151932 WR* 16 52 19.2477039480 -41 51 16.270066224 6.06 6.79 6.51 7.64   WN7h 326 0
61 HD 152234 s*b 16 54 01.8373785611 -41 48 22.987399147 4.92 5.64 5.45     B0.5Ia 201 0
62 HD 152233 SB* 16 54 03.5909222280 -41 47 29.841281484 5.93 6.72 6.59     O6II(f) 202 0
63 HD 152249 s*b 16 54 11.6395658856 -41 50 57.295111524 5.91 6.65 6.45     OC9Iab 254 0
64 NGC 6231 OpC 16 54 14.4 -41 48 53           ~ 562 0
65 Cl HM 1 12 * 17 18 42.8169069936 -38 49 50.367839016 14.46 14.09 12.57     O6I 13 0
66 CPD-33 4347 WR* 17 18 49.7249262168 -33 57 41.388161760   13.93 12.56 12.21   WN8/WC9 69 0
67 WRAY 15-1666 WR* 17 18 52.8750705984 -38 50 03.606746928 13.93 13.27 11.83 11.43   WN7 79 0
68 Cl HM 1 OpC 17 19 00 -38 49.0           ~ 52 0
69 CD-38 11746 WR* 17 19 00.5232022104 -38 48 51.247595664 13.01 12.48 11.02 10.55   WN8h 106 0
70 Cl HM 1 8 * 17 19 04.4329814016 -38 49 04.869862716 14.45 14.08 12.52     O5III(f) 19 0
71 CD-38 11748 ** 17 19 05.556576 -38 48 49.68000 13.03 12.76 11.26 10.68   O4.5Ifpe 38 0
72 Cl HM 1 6 * 17 19 06.0229903296 -38 46 45.008225868 13.53 13.18 11.64     O5.5Ifc 20 1
73 Cl Pismis 24 OpC 17 24 43.0 -34 12 23           ~ 130 0
74 2MASS J17244328-3412439 Y*O 17 24 43.2830173320 -34 12 43.893578664 13.68 13.36 11.95     O5V((f)) 24 0
75 HD 319718 ** 17 24 43.490 -34 11 57.03 12.28 11.94 10.44 10.05   O3.5If* 92 0
76 Cl Pismis 24 17 Y*O 17 24 44.7309068928 -34 12 02.698328196 13.61 13.33 11.84 11.35 9.61 O3.5III(f*) 47 0
77 2MASS J17244578-3409399 Y*O 17 24 45.7779508152 -34 09 39.851529768 14.53 14.21 12.73 12.30   O6V((f))z 34 1
78 HD 157504 WR* 17 25 08.8532916336 -34 11 12.498318168 12.80 12.10 10.68 10.39 11.546 WC7+O7-9 121 0
79 HD 157451 WR* 17 25 23.2779945960 -43 29 31.469964540 10 10.59 10.20 10.46   WC9 96 0
80 CD-33 12241 s*r 17 36 10.1192588472 -33 29 40.616892600 12.01 11.484 8.746 8.628   M0Ia 40 0
81 MR 74 WR* 17 36 19.8953017656 -33 26 12.271864344 16.01 14.87 13.18 12.99   WC9 93 1
82 Cl Trumpler 27 OpC 17 36 20 -33 31.0   8.24 6.7     ~ 100 1
83 V* V1082 Sco EB* 17 36 27.3946517448 -33 29 35.832155928 11.79 11.56 10.09 9.91   B0.7Ia 40 0
84 Cl Trumpler 27 27 * 17 36 29.9494444728 -33 26 34.187954784   15.47 13.31     O8III 12 0
85 GCIRS 16 Cl* 17 45 40.0 -29 00 28           ~ 387 0
86 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 792 0
87 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 561 0
88 MR 80 WR* 18 02 04.1244400656 -23 37 42.168277056   15.002 13.155 12.056   WC9 241 1
89 EM* AS 268 WR* 18 02 23.4574037952 -23 34 37.491692196   14.38 12.31 11.43   WN9h 106 0
90 HD 313643 WR* 18 04 43.6647313968 -21 09 30.555411624 13.58 13.27 12.02 11.67   WC9d 97 0
91 HD 165688 WR* 18 07 56.9609461704 -19 23 56.863324824 10.46 10.31 9.87 9.85   WN5-6b 162 0
92 HD 165763 WR* 18 08 28.4692108104 -21 15 11.183076540 7.16 7.54 7.82 8.55   WC6 286 0
93 PSR J1808-2024 Psr 18 08 39.32 -20 24 40.1           ~ 1316 2
94 MR 87 WR* 18 25 30.0135261024 -14 38 40.967308176 13.38 13.09 11.86 11.33   WN6-w 84 0
95 MR 89 WR* 18 41 00.8670061488 -04 26 14.484137676 13.1 12.97 11.93 11.67   WN7 74 2
96 EM* AS 320 WR* 18 44 13.1526105048 -03 47 57.775268904 13.7 13.340 13.983     WC9d 121 0
97 HD 177230 WR* 19 03 59.0233422072 -04 19 01.910240688 11.32 11.60 11.12     WN8 177 0
98 HD 187282 WR* 19 48 32.1967360032 +18 12 03.695582124 9.60 10.49 10.51     WN4(h)-w 202 0
99 HD 226868 HXB 19 58 21.6757355952 +35 12 05.784512688 9.38 9.72 8.91 8.42   O9.7Iabpvar 4590 0
100 HD 227018 * 19 59 49.1028248712 +35 18 33.550210836 8.75 9.35 9.00     O6.5V((f))z 110 0
101 HD 190864 Em* 20 05 39.8022808800 +35 36 27.991297908 7.18 7.93 7.78     O6.5III(f) 233 0
102 HD 190918 WR* 20 05 57.3244526328 +35 47 18.150756792 6.11 6.88 6.75     WN5+O9I 385 0
103 NGC 6871 OpC 20 06 07.9 +35 46 45   5.43 5.2     ~ 237 0
104 HD 191765 WR* 20 10 14.1928045152 +36 10 35.070683376 7.64 8.08 8.08     WN6-s 452 0
105 HD 192103 WR* 20 11 53.5274337792 +36 11 50.525765304 7.77 8.13 8.11     WC8+OB: 339 0
106 HD 192163 WR* 20 12 06.5418877464 +38 21 17.784181008 7.12 7.49 7.50     WN6(h)-s 715 1
107 HD 192641 WR* 20 14 31.7666855880 +36 39 39.598210224 7.80 8.20 7.91     WC7pd+O9V 347 0
108 HD 193077 WR* 20 17 00.0260987184 +37 25 23.785483116 7.82 8.32 8.01 8.71   WN5o+B? 297 0
109 HD 228841 Em* 20 18 29.6946566952 +38 52 39.774824724 9.08 9.50 9.01     O6.5Vn((f)) 66 0
110 HD 193595 * 20 19 31.3267230384 +39 03 26.230564836 8.5 9.08 8.78     O7V((f)) 64 0
111 HD 193576 WR* 20 19 32.4229160448 +38 43 53.959035756 8.15 8.53 8.00     WN5+O6II-V 721 0
112 HD 228943 * 20 19 47.2996683336 +38 35 44.967177060 10.1 10.09 9.35     O9.7III 27 0
113 HD 228969 * 20 20 09.5773014120 +38 39 32.288669892 10.02 10.12 9.54     O9.5IV 31 0
114 Cl Berkeley 86 OpC 20 20 20.6 +38 42 15           ~ 130 0
115 HD 229059 s*b 20 21 15.3643937664 +37 24 31.106402136 10.66 10.23 8.70     B2Iabe 102 0
116 LS II +37 73 * 20 21 19.2550073064 +37 23 24.728636868 12.4 12.18 10.92     B0.2III 26 0
117 HD 193928 WR* 20 21 31.7290073688 +36 55 12.773070696 10.67 10.60 9.78     WN5-w+O5V-III 205 0
118 Cl Berkeley 87 OpC 20 21 35.0 +37 25 14           ~ 141 0
119 BD+36 4032 Em* 20 21 38.6831894784 +37 25 15.208439844 11.94 11.64 10.30 10.09   O8.5III 29 0
120 WR 142 WR* 20 21 44.3438785440 +37 22 30.544989960   14.39 12.99 12.73 11.04 WO2 134 0
121 MR 110 WR* 20 32 03.0201049320 +41 15 20.499732216   15.99 13.97     WC5 85 0
122 Schulte 22 SB* 20 33 08.799 +41 13 18.21 14.33 13.59 11.55     O3If*+O6V((f)) 76 0
123 Schulte 9 s*b 20 33 10.7362926720 +41 15 08.222370372 13.38 12.77 10.96     O5I+O4III 243 0
124 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 1023 0
125 BD+40 4227A SB* 20 33 15.0781182864 +41 18 50.479292556 10.42 10.27 8.98 8.03 6.83 O6Ib(fc)+O4.5:III:(fc) 253 0
126 BD+41 3807 SB* 20 34 08.5147948176 +41 36 59.408503092 11.74 11.52 10.03     O5.5Ifc 137 0
127 HD 211564 WR* 22 16 24.0318845736 +55 37 36.767570232   11.72 11.61     WN3(h)-w 123 0
128 HD 213049 WR* 22 27 17.8187635824 +56 15 11.770681752   11.270 10.928 10.922   WC6 93 0
129 Cl Mrk 50 31 * 23 15 11.9353998432 +60 26 46.634136396 11.58 11.85 11.09     B2 17 0
130 HD 219460 ** 23 15 12.39033 +60 27 01.8129 10.23 10.51 9.89 9.563   B1II+WN4.5 135 0
131 HD 219460A * 23 15 12.3995306290 +60 27 01.845560649   10.97 10.57     B0.7II 128 0
132 Cl Mrk 50 OpC 23 15 14.5 +60 26 25   9.09 8.5     ~ 56 0
133 NAME Galactic Bar reg ~ ~           ~ 1458 0

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