2019A&A...626A..59C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST01:32:23

2019A&A...626A..59C - Astronomy and Astrophysics, volume 626A, 59-59 (2019/6-1)

A VLT/FLAMES survey for massive binaries in Westerlund 1. VI. Properties of X-ray bright massive cluster members.

CLARK J.S., RITCHIE B.W. and NEGUERUELA I.

Abstract (from CDS):


Context. X-ray emission from massive stars was first reported four decades ago, but the precise physics governing its formation as a function of stellar properties and binarity remains not fully understood. With the recent suggestion that such objects may be important sites of cosmic ray production, a better understanding of their high-energy properties is particularly timely.
Aims. The young massive cluster Westerlund 1 provides an ideal testbed for understanding this emission, with over 50 cluster members detected in historical X-ray observations. In the decade since these data were obtained, significant new multi-epoch observations of the cluster have been made, allowing a fundamental reappraisal of the nature of both X-ray bright and dark stars.
Methods. Optical spectroscopy permits accurate classification of cluster members, while multi-epoch observations of a sub-set allow identification and characterisation of the binary population.
Results. A total of 45 X-ray sources within Wd1 now have precise spectral classifications. Of these, 16 have been identified as candidate or confirmed massive binaries. X-ray emission is confined to O9-B0.5 supergiants, Wolf-Rayets and a small group of highly luminous interacting/post-interaction OB+OB binaries. Despite their presence in large numbers, no emission is seen from earlier, less evolved O stars or later, cooler B super-/hypergiants. A total of 22 stars have X-ray properties that are suggestive of a contribution from emission originating in a wind collision zone.
Conclusions. We suppose that the lack of X-ray emission from O giants is due to their comparatively low intrinsic bolometric luminosity if, as expected, they follow the canonical LX/Lbol relation for hot stars. The transition away from X-ray emission for OB supergiants occurs at the location of the bistability jump; we speculate that below this limit, stellar wind velocities are insufficient for internal, X-ray emitting shocks to form. Our results are consistent with recent findings that massive binaries are not uniformly brighter than single stars of comparable luminosity or spectral type, although it is noteworthy that the brightest and hardest stellar X-ray sources within Wd1 are all either confirmed or candidate massive, interacting/post-interaction binaries.

Abstract Copyright: © ESO 2019

Journal keyword(s): binaries: general - stars: early-type - stars: Wolf-Rayet - stars: winds - outflows - X-rays: stars

Simbad objects: 62

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Number of rows : 62

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 300 GiG 00 54 53.4460065856 -37 41 03.182962667 8.83 8.69 8.13 7.46   ~ 1305 2
2 V* CI Cam HXB 04 19 42.1353986687 +55 59 57.708146070 12.13 12.41 11.77 10.79 9.99 B0/2I[e] 224 0
3 HD 47129 SB* 06 37 24.0417003671 +06 08 07.376246443 5.23 6.11 6.06     O8I+O7.5III 368 0
4 * 29 CMa bL* 07 18 40.3796893709 -24 33 31.311819488 3.80 4.80 4.95 4.95 5.08 O7Iafpvar 396 0
5 HD 93403 SB* 10 45 44.1189478816 -59 24 28.162328313 6.72 8.46 8.27 8.35   O5.5III(fc)var 181 1
6 WR 48a WR* 13 12 39.65 -62 42 55.8           WC6 77 0
7 Cl* Westerlund 1 W 3002 * 16 46 54.2 -45 51 54   23.6 18.93 16.08 13.26 B0Iab 5 0
8 [CMN2008] J164658.2-455056 X 16 46 58.2 -45 50 56           ~ 3 0
9 Cl* Westerlund 1 W 56b * 16 46 58.8 -45 51 45   22.8 18.88 16.36 13.76 O9.5Ib 7 0
10 [CMN2008] J164659.0-455028 X 16 46 59.0 -45 50 28   21.3 17.82 15.60 13.63 ~ 2 0
11 Cl* Westerlund 1 W 1 * 16 46 59.4000616512 -45 50 46.717334625   21.9 18.37 16.09 13.65 ~ 5 0
12 WR 77b WR* 16 46 59.90 -45 55 25.6       16.9 13.0 WC9d 8 0
13 Cl* Westerlund 1 W 53 * 16 47 00.3870705334 -45 51 31.855415177   22.9 18.51 15.80 13.13 ~ 6 0
14 [CMN2008] J164701.0-455006 X 16 47 01.0295317884 -45 50 06.924784578           ~ 3 0
15 [CMN2008] C07-X6 V* 16 47 01.4381680891 -45 52 35.095830848   21.3 17.53 15.25 12.85 O9.5Ib 5 0
16 Cl* Westerlund 1 W 232 s*b 16 47 01.4381680892 -45 52 35.095830848   21.3 17.53 14.98 12.45 B0Iab 5 0
17 Cl* Westerlund 1 W 52 * 16 47 01.8447542252 -45 51 29.440031536   21.8 17.876 14.745 12.065 B1.5Ia 8 0
18 Cl* Westerlund 1 W 24 * 16 47 02.1549780316 -45 51 12.574291870   23.0 18.71 15.96 13.24 O9.2Ia 14 0
19 2MASS J16470235-4552340 X 16 47 02.36 -45 52 34.0   22.6 18.96 16.43 13.81 ~ 3 0
20 Cl* Westerlund 1 W 62a * 16 47 02.5 -45 51 37           O9.2Iab 7 0
21 Cl* Westerlund 1 W 47 * 16 47 02.5 -45 51 17   22.7 19.95 16.36 13.68 ~ 3 0
22 Cl* Westerlund 1 W 61b * 16 47 02.5661124892 -45 51 41.865044969   22.7 18.59 16.00 13.31 O9.5Iab 13 0
23 [CMN2008] C07-X4 * 16 47 02.7 -45 52 12   23.5 19.29 16.69 14.09 O9.2Iab 3 0
24 Cl* Westerlund 1 W 41 * 16 47 02.70 -45 50 56.9   21.3 17.87 15.39 12.78 O9.2Ia 12 0
25 Cl* Westerlund 1 W 38 * 16 47 02.8 -45 50 46   23.2 19.10 16.47 13.81 O9Iab 7 0
26 Cl* Westerlund 1 W 6 * 16 47 03.06 -45 50 23.8   22.2 18.41 15.80 13.16 O9.5B0.5Ia 8 0
27 Cl* Westerlund 1 W 10 s*b 16 47 03.3403089792 -45 50 34.601286210   22.720 18.516 15.257   O9.5/B0.5Iae 14 0
28 Cl* Westerlund 1 W 43 * 16 47 03.56 -45 50 57.6   22.8 18.05 15.378 12.647 O9.5B0.5Ia 14 0
29 Cl* Westerlund 1 W 65 * 16 47 03.8 -45 51 46   22.9 18.73 16.27 13.68 O9Ib 7 0
30 Cl Westerlund 1 OpC 16 47 04.00 -45 51 04.9           ~ 463 0
31 Cl* Westerlund 1 W 6a * 16 47 04.00 -45 50 21.0   22.2 18.41 15.80 13.16 B0.5Iab 7 0
32 Cl* Westerlund 1 CN G WR* 16 47 04.03 -45 51 25.1   22.7 20.87 17.75 14.68 WN7o 14 0
33 Cl* Westerlund 1 W 30 ** 16 47 04.11 -45 50 39.0   22.4 18.45 15.80 13.20 O+O 17 0
34 Cl* Westerlund 1 W 9 WR* 16 47 04.1422943113 -45 50 31.307461802   21.8 17.47 14.47 11.74 Be 46 0
35 WR 77k WR* 16 47 04.2024907825 -45 51 07.245158203   22.6 18.86 15.61 12.52 WN7 21 0
36 [CMN2008] J164704.4-455109 X 16 47 04.4 -45 51 09           ~ 3 0
37 [CMN2008] C07-X3 V* 16 47 04.55 -45 50 08.5   21.9 18.89 16.37 13.76 O9.2Ia 4 0
38 Cl* Westerlund 1 W 36 * 16 47 05.0818815492 -45 50 55.159484121   22.8 18.89 16.09 13.38 ~ 8 0
39 Cl* Westerlund 1 W 27 * 16 47 05.1556032855 -45 50 41.414756475   21.5 17.94 15.35 12.80 O9I+OI 7 0
40 WR 77n WR* 16 47 05.2111619515 -45 52 24.987049941   21.7 17.86 15.39 12.90 WC9d 23 0
41 WR 77o WR* 16 47 05.37 -45 51 04.7     20.99 17.50 14.37 WN7o 20 0
42 Cl* Westerlund 1 W 25 * 16 47 05.7848583644 -45 50 33.418949115   21.9 17.85 15.22 12.61 O9Iab 9 0
43 WR 77q WR* 16 47 06.01 -45 50 23.4       17.652 15.223 WN5o 11 0
44 WR 77p WR* 16 47 06.0558179916 -45 52 08.310667517     18.379 15.675 12.940 WC9 16 0
45 Cl* Westerlund 1 W 17 * 16 47 06.2491553642 -45 50 49.290357352   22.7 18.87 16.19 13.56 O9Iab 13 0
46 WR 77r WR* 16 47 06.28 -45 51 26.4     19 18.935 15.600 WN7o 13 0
47 Cl* Westerlund 1 W 13 EB* 16 47 06.4536718776 -45 50 26.067083031   21.1 17.19 14.63 12.06 BIa+ 28 0
48 [CMN2008] J164706.5-455039 WR* 16 47 06.60 -45 50 38.6   23.7 19.81 16.98 13.99 WN6o 6 0
49 Cl* Westerlund 1 W 15 * 16 47 06.6298019596 -45 50 29.720379477   22.8 18.96 16.38 13.75 O9.2Ia 21 0
50 [CMN2008] J164706.9-454940 X 16 47 07.01 -45 49 40.1       16.702 13.938 ~ 3 0
51 Cl* Westerlund 1 W 74 * 16 47 07.0789459358 -45 50 13.090797987       15.835 13.312 O9.2Ia 10 0
52 WR 77sa WR* 16 47 07.6210887572 -45 49 22.083635800           WN6h 6 0
53 WR 77sb WR* 16 47 07.6628412189 -45 52 35.973599868       16.886 14.047 WN6o 10 0
54 [B2007] J164707.84-455147.9 X 16 47 07.8197555904 -45 51 47.910822522       16.940 13.939 ~ 3 0
55 WR 77s WR* 16 47 08.3531944202 -45 50 45.405753222     19.69 16.59 13.68 WN7b 22 0
56 [CMN2008] J164711.5-455000 X 16 47 11.5 -45 50 00           ~ 3 0
57 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11533 0
58 MR 110 WR* 20 32 03.0200838781 +41 15 20.497485753   15.99 13.97     WC5 72 0
59 BD+40 4220 EB* 20 32 22.4241357648 +41 18 18.942382590 11.32 10.79 9.185     O6.5-7f+O5.5-6f 368 0
60 Schulte 12 s*b 20 32 40.9574572449 +41 14 29.276333992 16.1 14.45 11.702     B3-4Ia+ 358 0
61 Schulte 9 s*b 20 33 10.7366753544 +41 15 08.222187463 13.38 12.77 10.96     O4.5If 206 0
62 BD+40 4227A SB* 20 33 15.0780900764 +41 18 50.478859468 10.42 10.27 8.98 8.03 6.83 O6Ib(fc)+O4.5:III:(fc) 215 0

    Equat.    Gal    SGal    Ecl

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2020.07.04-01:32:23

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