2019A&A...623A..83C

Query : 2019A&A...623A..83C

2019A&A...623A..83C - Astronomy and Astrophysics, volume 623A, 83-83 (2019/3-1)

A VLT/FLAMES survey for massive binaries in Westerlund 1. V. The X-ray selected blue stragglers Wd1-27 and -30a.

CLARK J.S., NAJARRO F., NEGUERUELA I., RITCHIE B.W., GONZALEZ-FERNANDEZ C. and LOHR M.E.

Abstract (from CDS):


Context. Recent observational studies indicate that a large number of OB stars are found within binary systems which may be expected to interact during their lifetimes. Significant mass transfer or indeed merger of both components is expected to modify evolutionary pathways, facilitating the production of exceptionally massive stars which will present as blue stragglers. Identification and characterisation of such objects is crucial if the efficiency of mass transfer is to be established; a critical parameter in determining the outcomes of binary evolutionary channels.
Aims. The young and coeval massive cluster Westerlund 1 hosts a rich population of X-ray bright OB and Wolf-Rayet stars where the emission is attributed to shocks in the wind collision zones of massive binaries. Motivated by this, we instigated a study of the extremely X-ray luminous O supergiants Wd1-27 and -30a.
Methods. We subjected a multi-wavelength and -epoch photometric and spectroscopic dataset to quantitative non-LTE model atmosphere and time-series analysis in order to determine fundamental stellar parameters and search for evidence of binarity. A detailed examination of the second Gaia data release was undertaken to establish cluster membership.
Results. Both stars were found to be early/mid-O hypergiants with luminosities, temperatures and masses significantly in excess of other early stars within Wd1, hence qualifying as massive blue stragglers. The binary nature of Wd1-27 remains uncertain but the detection of radial velocity changes and the X-ray properties of Wd1-30a suggest that it is a binary with an orbital period ≤10 days. Analysis of Gaia proper motion and parallactic data indicates that both stars are cluster members; we also provide a membership list for Wd1 based on this analysis.
Conclusions. The presence of hypergiants of spectral types O to M within Wd1 cannot be understood solely via single-star evolution. We suppose that the early-B and mid-O hypergiants formed via binary-induced mass-stripping of the primary and mass-transfer to the secondary, respectively. This implies that for a subset of objects massive star-formation may be regarded as a two-stage process, with binary-driven mass-transfer or merger yielding stars with masses significantly in excess of their initial "birth" mass.

Abstract Copyright: © ESO 2019

Journal keyword(s): blue stragglers - binaries: general - stars: early-type - stars: evolution - stars: individual: Wd1-27 - stars: individual: Wd1-30a

Simbad objects: 128

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Number of rows : 128
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 NGC 346 Cl* 00 59 04.4000 -72 10 39.000           ~ 490 0
2 Cl* NGC 346 MPG 782 EB* 00 59 30.37 -72 09 09.7 13.06 14.19 14.35   14.82 B1: 11 0
3 HD 13854 s*b 02 16 51.7162480872 +57 03 18.882144756 6.10 6.76 6.48 6.14 5.95 B1Iab 213 0
4 HD 14434 Em* 02 21 52.4121560832 +56 54 18.032028876 7.87 8.65 8.49 8.29 8.20 O5.5Vnn((f))p 187 0
5 HD 14947 s*b 02 26 46.9899705528 +58 52 33.118732380 7.83 8.44 7.98     O4.5If 254 0
6 HD 15570 Em* 02 32 49.4207394600 +61 22 42.089384892 8.40 8.80 8.11 7.41 6.86 O4If 305 0
7 * alf Cam s*b 04 54 03.0113886719 +66 20 33.633625509 3.47 4.34 4.29 4.18 4.18 O9Ia 661 1
8 * eps Ori s*b 05 36 12.81335 -01 12 06.9089 0.48 1.51 1.69 1.76 1.93 B0Ia 896 0
9 RMC 136 Cl* 05 38 42.396 -69 06 03.36   5.81 5.40     ~ 2019 2
10 HD 115842 s*b 13 20 48.3393402216 -55 48 02.482824528 5.70 6.39 6.09 5.77 5.52 B0.5Ia 154 0
11 HD 134959 s*b 15 15 24.0871041696 -59 04 29.296677756 9.05 9.14 8.10 8.642   B2Ia 80 0
12 [RCN2009] W3002 s*b 16 46 54.24 -45 51 54.7   23.6 18.93 16.08 13.26 B0Iab 9 0
13 HD 151018 * 16 46 56.1174957336 -45 53 14.312361444 8.9 9.93 9.37 9.35   O9Ib 67 0
14 Cl* Westerlund 1 W 86 * 16 46 57.1589551488 -45 50 09.938630292   22.9 18.76 16.43 14.00 O9.5Ib 11 0
15 Cl* Westerlund 1 W 373 s*b 16 46 57.7255119168 -45 53 20.035273668       14.741 12.318 B0Iab 12 0
16 Cl* Westerlund 1 W 228b * 16 46 58.0541909424 -45 53 00.932401356           O9Ib 11 0
17 Cl* Westerlund 1 W 55 s*b 16 46 58.4205093840 -45 51 31.294157724   21.6 18.030 15.283 12.758 B0Ia 17 0
18 Cl* Westerlund 1 W 56b * 16 46 58.8667320511 -45 51 45.947165816   22.8 18.88 16.36 13.76 O9.5Ib 12 0
19 Cl* Westerlund 1 W 56a s*b 16 46 58.9489660320 -45 51 48.908566764   21.7 17.46 14.81 12.15 B1.5Ia 14 0
20 Cl* Westerlund 1 W 84 * 16 46 59.0490595608 -45 50 28.293859689   21.3 17.82 15.60 13.63 O9.5Ib 13 0
21 Cl* Westerlund 1 W 1 s*b 16 46 59.4000262680 -45 50 46.721009148   21.9 18.37 16.09 13.65 O9.5Iab 10 0
22 Cl* Westerlund 1 W 2 s*b 16 46 59.7175806088 -45 50 51.190946043   20.4 16.978 14.287 11.771 B2Ia 18 0
23 Cl* Westerlund 1 CN N WR* 16 46 59.9151721464 -45 55 25.670942256       16.9 13.0 WC9d 15 0
24 Cl* Westerlund 1 W 53 s*b 16 47 00.3870731784 -45 51 31.849633872   22.9 18.51 15.80 13.13 OBIa+OBIa 11 0
25 Cl* Westerlund 1 CN I WR* 16 47 00.8820136008 -45 51 20.517977916       17.336 14.340 WN8o 19 0
26 Cl* Westerlund 1 W 21 s*b 16 47 01.1124528826 -45 51 13.583454380   22.5 18.41 15.619 12.861 B0.5Ia 12 0
27 Cl* Westerlund 1 W 50b * 16 47 01.1722949256 -45 50 26.807447580   22.8 19.66 17.21 14.69 O9III 10 0
28 Cl* Westerlund 1 W 57 s*b 16 47 01.3600091808 -45 51 45.804003408   20.7 16.877 13.83 11.13 B4Ia 20 0
29 Cl* Westerlund 1 W 59 LP? 16 47 01.4018401611 -45 51 50.717305812   23.1 18.97 16.33 13.64 ~ 5 0
30 Cl* Westerlund 1 BKS H s*y 16 47 01.4269856784 -45 50 37.248841536   18.781 14.47 11.80 9.15 F3Ia+ 29 0
31 Cl* Westerlund 1 W 78 s*b 16 47 01.5500127120 -45 49 57.922981500   21.0 17.413 14.621 12.04 B1Ia 13 0
32 WR 77d WR* 16 47 01.5976561900 -45 51 45.244547387           WN7o 14 0
33 [RCN2009] W3005 s*b 16 47 01.6814988264 -45 52 58.067536008       15.393 12.966 O9.5Iab 14 0
34 Cl* Westerlund 1 W 52 s*b 16 47 01.8449474352 -45 51 29.434394880   21.8 17.876 14.745 12.065 B1.5Ia 13 0
35 Cl* Westerlund 1 W 49 s*b 16 47 01.9027544712 -45 50 31.660433592   22.6 18.76 16.392 13.638 B0Iab 14 0
36 Cl* Westerlund 1 W 24 s*b 16 47 02.1561069816 -45 51 12.581922276   23.0 18.71 15.96 13.24 O9Iab 19 0
37 Cl* Westerlund 1 W 12 s*y 16 47 02.2214295629 -45 50 58.987616665   22.0 17.575 13.611 10.42 A5Ia+ 27 0
38 Cl* Westerlund 1 W 11 s*b 16 47 02.2390158456 -45 50 47.186514564   21.2 17.508 14.599 11.898 B2Ia 17 0
39 Cl* Westerlund 1 W 61a s*b 16 47 02.2999985640 -45 51 41.772039336   21.2 17.506 14.633 12.01 B0.5Ia 16 0
40 Cl Westerlund 1 Cl* 16 47 02.4 -45 51 07           ~ 569 0
41 Cl* Westerlund 1 W 48 V* 16 47 02.4593648232 -45 51 24.952273200       16.818 13.966 ~ 5 0
42 Cl* Westerlund 1 CN J WR* 16 47 02.4735872095 -45 50 59.898935502           WN5h 14 0
43 Cl* Westerlund 1 W 62a LP? 16 47 02.5204504462 -45 51 38.051924860           B0.5Ib 10 0
44 Cl* Westerlund 1 W 61b s*b 16 47 02.5662082776 -45 51 41.864431536   22.7 18.59 16.00 13.31 O9.5Iab 17 0
45 Cl* Westerlund 1 W 23a s*b 16 47 02.5776330614 -45 51 08.902293204   22.1 18.316 14.986 12.081 B2Ia+B:I? 18 0
46 Cl* Westerlund 1 W 41 s*b 16 47 02.7105467198 -45 50 56.972033345   21.3 17.87 15.39 12.78 O9Iab 16 0
47 Cl* Westerlund 1 W 38 s*b 16 47 02.8628531323 -45 50 46.145964246   23.2 19.10 16.47 13.81 O9Iab 12 0
48 Cl* Westerlund 1 W 6b * 16 47 02.9390384334 -45 50 22.480676456   23.6 20.20 17.91 15.25 O9.5III 10 0
49 WR 77f WR* 16 47 02.9772955944 -45 50 19.713734556   21.552 17.792 15.035 12.508 WNL/BIa+ 33 0
50 Cl* Westerlund 1 W 6a s*b 16 47 03.0477797919 -45 50 23.748131606   22.2 18.41 15.80 13.16 B0.5Iab 19 0
51 Cl* Westerlund 1 W 54 s*b 16 47 03.06 -45 51 30.5           B0.5Iab 7 0
52 Cl* Westerlund 1 W 237 s*r 16 47 03.1097130192 -45 52 18.960733164   22.8 19.008 13.634 9.19 M3I 29 0
53 WR 77g WR* 16 47 03.15 -45 50 43.8     19     WC8 16 0
54 Cl* Westerlund 1 W 42 s*b 16 47 03.2521856424 -45 50 52.195013052         10.764 B9Ia+ 19 0
55 Cl* Westerlund 1 W 10 s*b 16 47 03.3405625992 -45 50 34.603317456   22.720 18.516 15.257   O9.5/B0.5Iae 18 0
56 Cl* Westerlund 1 W 63a s*b 16 47 03.4010407564 -45 51 57.852956239   22.6 18.56 16.20 13.68 B0Iab 9 0
57 Cl* Westerlund 1 W 43b s*b 16 47 03.5274881368 -45 50 56.525344948           B1Ia 7 0
58 Cl* Westerlund 1 W 43a s*b 16 47 03.5568442836 -45 50 57.728053296   22.8 18.05 15.22 12.26 B0Ia 14 0
59 Cl* Westerlund 1 W 46b * 16 47 03.61 -45 51 20.0           O9.5Ib 7 0
60 Cl* Westerlund 1 W 7 s*b 16 47 03.6281794392 -45 50 14.365482036   20.0 15.972 12.73 9.99 B5Ia+ 28 0
61 Cl* Westerlund 1 BKS F s*y 16 47 03.6850109472 -45 50 43.536110712     15.05     F5Ia+ 23 0
62 Cl* Westerlund 1 W 43c * 16 47 03.7585229164 -45 50 58.441368189   20.4 18.35 16.18 13.66 O9Ib 10 0
63 Cl* Westerlund 1 W 31 s*b 16 47 03.7862784096 -45 50 40.366601376           B0I+OB 11 0
64 Cl* Westerlund 1 W 65 * 16 47 03.8973039959 -45 51 46.495252717   22.9 18.73 16.27 13.68 O9Ib 12 0
65 Cl* Westerlund 1 W 46a s*b 16 47 03.9147803107 -45 51 19.743263385   23.0 18.55 15.537 12.499 B1Ia 17 0
66 WR 77i WR* 16 47 03.9628130472 -45 51 37.672066152     19.79 16.906 13.949 WC9d 17 0
67 Cl* Westerlund 1 CN G WR* 16 47 04.0152346631 -45 51 25.019757928   22.7 20.87 17.75 14.68 WN7o 22 0
68 Cl* Westerlund 1 W 30 ** 16 47 04.1126936513 -45 50 39.164057275   22.4 18.45 15.80 13.20 O4-5Ia+ 23 0
69 Cl* Westerlund 1 W 33 s*b 16 47 04.1256274968 -45 50 48.488202564   20.090 15.61 12.803 10.04 B5Ia+ 23 0
70 Cl* Westerlund 1 W 60 s*b 16 47 04.1335644720 -45 51 52.259535324   22.8 18.50 16.041 13.384 B0Iab 19 0
71 Cl* Westerlund 1 W 9 WR* 16 47 04.1419806984 -45 50 31.311670632   21.8 17.47 14.47 11.74 sgB[e] 52 0
72 Cl* Westerlund 1 W 35 s*b 16 47 04.2023052264 -45 50 53.727473868   22.7 18.59 16.00 13.31 O9Iab 14 0
73 WR 77k WR* 16 47 04.2072122904 -45 51 07.177760892   22.6 18.86 15.61 12.52 WN7 27 0
74 Cl* Westerlund 1 CN H WR* 16 47 04.2489212873 -45 51 20.211867845           WC9d 15 0
75 Cl* Westerlund 1 W 34 s*b 16 47 04.3941837044 -45 50 47.222852634   22.1 18.15 15.40 12.69 B0Ia 11 0
76 Cl* Westerlund 1 W 29 s*b 16 47 04.4118843432 -45 50 39.933732768   22.6 18.66 16.02 13.38 O9.5/B0.5Ia 12 0
77 Cl* Westerlund 1 CN C WR* 16 47 04.4125871144 -45 51 03.606604135           WC9d 16 0
78 Cl* Westerlund 1 W 238 s*b 16 47 04.4263582176 -45 52 27.788277972   21.4 17.820 14.98 12.45 B1Iab 16 0
79 Cl* Westerlund 1 W 28 s*b 16 47 04.6646286552 -45 50 38.503394520   20.9 17.146 14.303 11.64 B2Ia 15 0
80 Cl* Westerlund 1 W 20 s*r 16 47 04.6967287296 -45 51 23.953706496       15.660   M6I 24 0
81 Cl* Westerlund 1 W 8 s*y 16 47 04.7959778348 -45 50 25.013789709   19.9 15.913 12.64 9.89 F8Ia+ 22 0
82 Cl* Westerlund 1 W 19 s*b 16 47 04.8672458112 -45 50 59.295902136   22.6 18.784 15.366 12.452 B1Ia 18 0
83 Cl* Westerlund 1 W 8b s*b 16 47 04.95 -45 50 26.7           B1.5Ia 10 0
84 Cl* Westerlund 1 W 36 s*b 16 47 05.0826653568 -45 50 55.155662808   22.8 18.89 16.09 13.38 OBIa+OBIa 12 0
85 Cl* Westerlund 1 W 27 s*b 16 47 05.1550269480 -45 50 41.418677508   21.5 17.94 15.35 12.80 O9I+OI 13 0
86 Cl* Westerlund 1 CN F WR* 16 47 05.2114579896 -45 52 24.985725096   21.7 17.86 15.39 12.90 WC9d 31 0
87 Cl* Westerlund 1 CN B WR* 16 47 05.3717585660 -45 51 04.811705369     20.99 17.50 14.37 WN7o 30 0
88 2MASS J16470540-4550367 s*r 16 47 05.4076906176 -45 50 36.617071668   22.1 16.79 12.63 9.19 M2-5Ia 36 0
89 Cl* Westerlund 1 W 18 s*b 16 47 05.7082494087 -45 50 50.480383849   21.2 17.610 14.898 12.228 B0.5Ia 11 0
90 Cl* Westerlund 1 CN R WR* 16 47 05.9726730842 -45 50 23.072495547       17.652 15.223 WN5o 21 0
91 Cl* Westerlund 1 W 39a * 16 47.1 -45 51           ~ 3 0
92 Cl* Westerlund 1 W 37 * 16 47 06.0112607572 -45 50 47.478171168   22.8 19.11 16.40 13.65 O9Ib 8 0
93 Cl* Westerlund 1 CN E WR* 16 47 06.0667110144 -45 52 08.266249200     18.379 15.675 12.940 WC9 23 0
94 Cl* Westerlund 1 W 17 s*b 16 47 06.2490500592 -45 50 49.292687328   22.7 18.87 16.19 13.56 O9Iab 18 0
95 Cl* Westerlund 1 CN D WR* 16 47 06.2554455566 -45 51 26.391243810       18.935 15.600 WN7o 21 0
96 Cl* Westerlund 1 W 265 s*y 16 47 06.2785465416 -45 49 23.774098692   22.0 17.739 13.62 10.54 F1-5Ia+ 26 0
97 Cl* Westerlund 1 W 13 WR* 16 47 06.4540771320 -45 50 26.072579796   21.1 17.19 14.63 12.06 WNL/BIa+ 35 0
98 Cl* Westerlund 1 W 16 sg* 16 47 06.6158603112 -45 50 42.186706944   20.5 16.248 12.82 9.90 A5Ia+ 29 0
99 Cl* Westerlund 1 W 15 * 16 47 06.6306037464 -45 50 29.723762580   22.8 18.96 16.38 13.75 O9Ib 26 0
100 Cl* Westerlund 1 W 74 s*b 16 47 07.0783996992 -45 50 13.086504168       15.835 13.312 O9.5Iab 15 0
101 Cl* Westerlund 1 W 243 s*b 16 47 07.5040736160 -45 52 29.123491188   19.873 15.730     LBV 61 0
102 Cl* Westerlund 1 CN O WR* 16 47 07.6630825488 -45 52 35.964833052       16.886 14.047 WN6o 16 0
103 WR 77sc WR* 16 47 08.3538521592 -45 50 45.414739212     19.69 16.59 13.68 WN7b 29 0
104 Cl* Westerlund 1 W 71 s*b 16 47 08.4584673360 -45 50 49.338181284   21.5 17.531 14.158 11.16 B2.5Ia 22 0
105 2MASS J16470892-4549585 s*r 16 47 08.9198319768 -45 49 58.452357324     16.70     M4Ia 26 0
106 Cl* Westerlund 1 W 70 s*b 16 47 09.3836656992 -45 50 49.668960804   21.2 16.88 14.10 11.352 B3Ia 18 0
107 PSR J1647-4552 Psr 16 47 10.18 -45 52 16.7           ~ 198 1
108 [RCN2009] W3003 V* 16 47 11.6073210840 -45 49 22.478619972   23.1 19.08 16.211 13.314 B0Ib 12 0
109 [RCN2009] W3004 s*b 16 47 13.3832726280 -45 49 10.636397724   23.2 18.93 15.960 12.990 B0Iab 11 0
110 NAME Sco OB 1 As* 16 53.5 -41 57           ~ 217 0
111 HD 152233 SB* 16 54 03.5909222280 -41 47 29.841281484 5.93 6.72 6.59     O6II(f) 194 0
112 HD 152248 Y*O 16 54 10.0618206816 -41 49 30.139291596 5.56 6.15 6.088     O7Iabf+O7Ib(f) 260 0
113 NGC 6231 OpC 16 54 10.8 -41 48 43           ~ 538 0
114 HD 153919 HXB 17 03 56.7725629224 -37 50 38.913331452 6.06 6.78 6.51 6.08 5.90 O6Iafcp 814 1
115 HD 154368 s*b 17 06 28.3687759224 -35 27 03.760593156 6.10 6.63 6.13 7.12   O9.5Iab 294 0
116 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14436 0
117 GCIRS 7 * 17 45 39.987 -29 00 22.24           M2 369 0
118 GCIRS 8 * 17 45 40.14 -28 59 58.7           O 72 0
119 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 738 0
120 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 526 0
121 WR 102j WR* 17 46 17.53 -28 49 29.0           WN9 13 0
122 V* RY Sct Be* 18 25 31.4771300232 -12 41 24.192361500 10.25 10.38 9.12 9.46   O9.7Ibep 300 2
123 HD 190918 WR* 20 05 57.3244526328 +35 47 18.150756792 6.11 6.88 6.75     WN5+O9I 369 0
124 NGC 6871 OpC 20 06 11.5 +35 45 54   5.43 5.2     ~ 225 0
125 Ass Cyg OB 3 As* 20 07 +35.9           ~ 182 0
126 HD 192639 s*b 20 14 30.4275801672 +37 21 13.816276704 6.83 7.46 7.11     O7.5Iabf 292 0
127 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 945 0
128 NGC 7789 OpC 23 57 20.2 +56 43 34   7.68 6.7     ~ 528 0

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