2017A&A...608A..34G


Query : 2017A&A...608A..34G

2017A&A...608A..34G - Astronomy and Astrophysics, volume 608A, 34-34 (2017/12-1)

On the optically thick winds of Wolf-Rayet stars.

GRAFENER G., OWOCKI S.P., GRASSITELLI L. and LANGER N.

Abstract (from CDS):

Context. The classical Wolf-Rayet (WR) phase is believed to mark the end stage of the evolution of massive stars with initial masses higher than ∼25M. Stars in this phase expose their stripped cores with the products of H- or He-burning at their surface. They develop strong, optically thick stellar winds that are important for the mechanical and chemical feedback of massive stars, and that determine whether the most massive stars end their lives as neutron stars or black holes. The winds of WR stars are currently not well understood, and their inclusion in stellar evolution models relies on uncertain empirical mass-loss relations.
Aims. We investigate theoretically the mass-loss properties of H-free WR stars of the nitrogen sequence (WN stars).
Methods. We connected stellar structure models for He stars with wind models for optically thick winds and assessed the degree to which these two types of models can simultaneously fulfil their respective sonic-point conditions.
Results. Fixing the outer wind law and terminal wind velocity νinf, we obtain unique solutions for the mass-loss rates of optically thick, radiation-driven winds of WR stars in the phase of core He-burning. The resulting mass-loss relations as a function of stellar parameters agree well with previous empirical relations. Furthermore, we encounter stellar mass limits below which no continuous solutions exist. While these mass limits agree with observations of WR stars in the Galaxy, they contradict observations in the LMC.
Conclusions. While our results in particular confirm the slope of often-used empirical mass-loss relations, they imply that only part of the observed WN population can be understood in the framework of the standard assumptions of a smooth transonic flow and compact stellar core. This means that alternative approaches such as a clumped and inflated wind structure or deviations from the diffusion limit at the sonic point may have to be invoked. Qualitatively, the existence of mass limits for the formation of WR-type winds may be relevant for the non-detection of low-mass WR stars in binary systems, which are believed to be progenitors of Type Ib/c supernovae. The sonic-point conditions derived in this work may provide a possibility to include optically thick winds in stellar evolution models in a more physically motivated form than in current models.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: Wolf-Rayet - stars: early-type - stars: atmospheres - stars: mass-loss - stars: winds, outflows - stars: winds, outflows

Simbad objects: 58

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Number of rows : 58
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 HD 4004 WR* 00 43 28.3971737448 +64 45 35.384652468 10.28 10.718 10.138     WN4-s 197 0
2 HD 6327 WR* 01 05 23.0143603 +60 25 18.965197   11.49 11.33     WN2-w 120 0
3 Brey 1 WR* 04 45 32.2724972352 -70 15 10.892770740 15.001 15.711 15.92 15.75 15.643 WN3b 38 0
4 Brey 2 WR* 04 49 36.2527075920 -69 20 54.744608760 15.633 16.495 16.579   16.447 WN2b(h) 35 0
5 Brey 3 WR* 04 52 57.3970420344 -66 41 13.495924752 13.793 14.531 14.640   14.527 WN4b 40 0
6 Brey 4 WR* 04 54 28.0891890576 -69 12 50.797294596 15.957 16.715 16.742   16.363 WN2b 30 0
7 HD 32109 WR* 04 55 31.3415815464 -67 30 02.683346940 12.893 13.46 13.81 13.95 13.512 WN4b 74 0
8 HD 268847 WR* 04 59 51.5602106760 -67 56 55.438699560 13.658 14.21 14.58 14.75 14.426 WN4b 54 0
9 HD 269015 WR* 05 04 12.3240087744 -70 03 55.402898508 13.183 14.07 14.28 14.40 14.108 WN4o 47 0
10 BAT99 23 WR* 05 13 56.0309726688 -67 24 36.498713292   17.29 16.98     WN3(h) 14 0
11 HD 34783 WR* 05 14 12.7026762984 -69 19 26.110131672 13.668 14.115 14.49 14.55 14.150 WN4b 45 0
12 Brey 20 WR* 05 16 38.8431915960 -69 16 40.826569980 13.791 14.345 14.48 15.05 14.336 WN4b 39 0
13 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17416 0
14 Brey 30 WR* 05 24 54.3452003016 -66 14 11.166920160 16.080 16.545 16.328   15.915 WN3o 20 0
15 HD 269549 WR* 05 26 42.5908088736 -69 06 57.344865912 14.308 14.53 14.76 15.11 14.589 WN4b 46 0
16 Brey 38 WR* 05 28 17.9135754480 -69 02 35.894733612   15.22 15.26     WN4o 32 0
17 HD 269624 WR* 05 29 31.6376299080 -68 54 28.817207028 14.008 14.491 14.781 14.81 14.703 WN4b 46 1
18 Brey 42 WR* 05 30 02.4527669472 -68 45 18.387861660 14.146 14.939 15.201   15.213 WN3b 32 0
19 HD 269692 WR* 05 31 32.8704053376 -67 40 46.605246924 13.592 14.28 14.49 14.70 14.519 WN4b 46 0
20 Brey 45 WR* 05 31 34.3667195064 -67 16 29.329573872 14.146 14.696 14.897 15.02 14.835 WN4b 32 0
21 Brey 55 WR* 05 35 15.18 -69 05 43.1 15.612 15.542 15.389     WN4o 22 0
22 HD 269848 WR* 05 35 54.0299886024 -67 02 48.969864816 13.694 14.06 14.34 14.65 14.440 WN4o 36 0
23 Brey 69 WR* 05 37 11.4810561480 -69 07 38.183877948 15.959 16.427 16.301   15.936 WN3o 25 0
24 Brey 70a WR* 05 37 35.7045940032 -69 08 40.251941520 17.387 17.957 16.924   16.324 WN4b/WCE 29 0
25 HD 269908 WR* 05 38 27.7009045560 -69 29 58.546136796 14.243 14.40 14.29 14.59 14.230 WN4b 43 0
26 Brey 93a WR* 05 39 36.1929497064 -69 39 11.174764248           WN4 17 0
27 Brey 96 WR* 05 40 50.7849505008 -69 26 31.687448928 14.965 15.549 15.718   15.494 WN3b 23 0
28 Brey 98 WR* 05 44 53.7279459672 -67 10 36.132882708       14.571 14.45 WN3/5 32 0
29 Brey 99 WR* 05 45 24.1680967944 -67 05 56.733951696 14.221 14.69 14.81 14.88 14.371 WN4b(h) 38 0
30 HD 270149 WR* 05 46 46.3470746448 -67 09 58.269315024 14.025 14.20 14.48 14.76 14.524 WN4b 54 0
31 HD 50896 WR* 06 54 13.0439608392 -23 55 42.023319852 5.74 6.63 6.91 7.74   WN4b 773 0
32 HD 56925 WR* 07 18 29.1311435688 -13 13 01.513932528 11.21 11.74 11.56 11.40   WN4b 173 0
33 HD 89358 WR* 10 17 02.2743231360 -57 54 46.875258324 11.1 11.19 10.83 10.59   WN4-s 174 1
34 WR 20 WR* 10 19 18.4020394728 -59 09 38.849457528   15.34 14.60     WN5-w 38 0
35 WR 34 WR* 11 00 06.4565444280 -61 26 30.107994972   15.26 14.50     WN5-w 35 0
36 WR 36 WR* 11 02 32.9786756376 -59 26 20.909947272   13.90 12.94 12.86   WN5-s 35 0
37 WR 37 WR* 11 05 13.9026194544 -61 20 41.185677192   17.40 16.0     WN4-s 39 0
38 MR 39 WR* 11 16 57.8368404744 -59 26 23.893309392   13.04 12.79 12.71   WN4-w 54 0
39 HD 104994 WR* 12 05 18.7204232424 -62 03 10.140656832 9.95 10.94 10.93 11.03   WN3p-w 166 0
40 MR 45 WR* 13 18 23.3593835760 -62 28 21.220535604   15.53 14.32 13.97   WN4-w 47 0
41 MR 48 WR* 13 32 43.7633368296 -65 01 27.837319620 12.85 13.20 12.73 12.61   WN5-w 55 0
42 HD 117688 WR* 13 33 30.1197052368 -62 19 01.214335740 8.69 10.81 10.90 10.44   WN7 130 0
43 MR 53 WR* 14 13 03.5252119752 -65 26 52.707986592 11.93 12.51 12.32 12.21   WN5-w 73 0
44 WRAY 16-154 WR* 14 31 06.13 -61 20 59.5   15.82 14.22     WN6-s 32 1
45 WRAY 15-1254 WR* 14 50 58.2650618251 -59 51 26.428849251 14.29 13.96 12.47 11.85   WN6 43 0
46 MR 55 WR* 15 15 32.6272277376 -59 02 30.695283672 12.46 12.56 11.84 11.63   WN6-w 70 0
47 WR 74 WR* 16 16 13.7935305271 -51 36 41.786124295   15.53 14.01     WN7 29 0
48 HD 147419 WR* 16 24 26.2279587024 -51 32 06.061114140   11.46 10.50 10.74   WN6-s 111 0
49 THA 31-1 WR* 17 11 21.7008844704 -39 53 21.976096632   14.18 13.01 12.54   WN7 41 0
50 WR 91 WR* 17 20 22.0229832912 -38 56 48.381120240   17.70 16.2     WN7 35 0
51 HD 318139 WR* 17 42 09.7606723248 -32 33 24.800937012   13.93 12.78 12.20   WN7 47 0
52 HD 165688 WR* 18 07 56.9609461704 -19 23 56.863324824 10.46 10.31 9.87 9.85   WN5-6b 156 0
53 MR 87 WR* 18 25 30.0135261024 -14 38 40.967308176 13.38 13.09 11.86 11.33   WN6-w 81 0
54 MR 89 WR* 18 41 00.8670061488 -04 26 14.484137676 13.1 12.97 11.93 11.67   WN7 72 2
55 HD 177230 WR* 19 03 59.0233422072 -04 19 01.910240688 11.32 11.60 11.12     WN8 171 0
56 MR 96 WR* 19 48 18.2649812592 +30 26 52.672284420   13.3 13.4     WN4-w 35 0
57 HD 191765 WR* 20 10 14.1928045152 +36 10 35.070683376 7.64 8.08 8.08     WN6-s 441 0
58 WR 149 WR* 21 07 11.6933616840 +48 25 36.238552680   15.90 14.70     WN5-s 45 0

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