2005A&A...439.1107D


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.26CET17:41:35

2005A&A...439.1107D - Astronomy and Astrophysics, volume 439, 1107-1125 (2005/9-1)

Asphericity and clumpiness in the winds of Luminous Blue Variables.

DAVIES B., OUDMAIJER R.D. and VINK J.S.

Abstract (from CDS):

We present the first systematic spectropolarimetric study of Luminous Blue Variables (LBVs) in the Galaxy and the Magellanic Clouds, in order to investigate the geometries of their winds. We find that at least half of our sample show changes in polarization across the strong Hα emission line, indicating that the light from the stars is intrinsically polarized and therefore that asphericity already exists at the base of the wind. Multi-epoch spectropolarimetry on four targets reveals variability in their intrinsic polarization. Three of these, AG Car, HR Car and P Cyg, show a position angle (PA) of polarization which appears random with time. Such behaviour can be explained by the presence of strong wind-inhomogeneities, or ``clumps'' within the wind. Only one star, R 127, shows variability at a constant PA, and hence evidence for axi-symmetry as well as clumpiness. However, if viewed at low inclination, and at limited temporal sampling, such a wind would produce a seemingly random polarization of the type observed in the other three stars. Time-resolved spectropolarimetric monitoring of LBVs is therefore required to determine if LBV winds are axi-symmetric in general. The high fraction of LBVs (>50%) showing intrinsic polarization is to be compared with the lower ∼20-25% for similar studies of their evolutionary neighbours, O supergiants and Wolf-Rayet stars. We anticipate that this higher incidence is due to the lower effective gravities of the LBVs, coupled with their variable temperatures within the bi-stability jump regime. This is also consistent with the higher incidence of wind asphericity that we find in LBVs with strong Hα emission and recent (last ∼10-years) strong variability.

Abstract Copyright:

Journal keyword(s): techniques: polarimetric - stars: mass-loss - stars: winds, outflows - stars: early-type - stars: activity - stars: evolution

Simbad objects: 33

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Number of rows : 33

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 HD 6884 s*b 01 07 18.2183812921 -72 28 03.658768522   10.32 10.2     B9Ia0ek 114 0
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5856 1
3 HD 32034 s*b 04 55 11.0859350434 -67 10 10.409058575 9.13 9.756 9.715 9.70 9.51 B9Iae 68 0
4 HD 269006 s*b 05 02 07.3944119328 -71 20 13.118657760 9.93 10.60 10.55 10.43 10.38 LBV 235 0
5 V* S Dor sg* 05 18 14.3572490675 -69 15 01.148131817 9.08 10.39 10.25 9.74 9.14 A5Iaeq 352 0
6 HD 269662 sg* 05 30 51.4755593461 -69 02 58.591230109 10.23 10.52 10.28 10.40 10.390 A0Ia 93 0
7 HD 269700 s*b 05 31 52.2818792698 -68 32 38.856584550 9.71 10.56 10.54 10.38 10.38 B1.5Iaeq 78 0
8 HD 269858 s*b 05 36 43.6942807271 -69 29 47.449383685   10.24 10.15 9.95 9.05 LBV 268 2
9 CPD-69 463 s*y 05 38 51.6167474749 -69 08 07.314653596 11.93 12.45 12.014     F7Ia 81 1
10 * 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 853 0
11 * phi Vel * 09 56 51.7416742 -54 34 04.039043 2.81 3.35 3.45 3.51 3.59 B5Ib 123 0
12 * eta Leo * 10 07 19.9518606 +16 45 45.580270 3.17 3.39 3.41 3.32 3.35 A0Ib 321 0
13 HD 90177 s*b 10 22 53.8426931454 -59 37 28.361118869 9.16 9.66 8 8.15   LBV 308 0
14 HD 92207 sg* 10 37 27.0681943657 -58 44 00.015326487 5.71 5.95 5.45     A0Ia 146 0
15 HD 92964 s*b 10 42 40.5663586355 -59 12 56.727932428 5.12 5.78 5.51 5.30 5.00 B2.5Ia 139 0
16 NAME Homunculus Nebula ISM 10 45 03.5 -59 41 04           ~ 330 1
17 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2254 0
18 HD 93737 sg* 10 48 05.4069266146 -59 55 08.980982797   6.230 6.015     A0Ia/ab 50 0
19 WRAY 15-682 WR* 10 53 59.5776214569 -60 26 44.358376205   11.64 10.85 10.56   WN11h 139 3
20 V* AG Car WR* 10 56 11.5779283438 -60 27 12.809532379 7.00 7.57 6.96 7.73   WN11h 598 0
21 MR 35 s*b 11 08 40.0633818066 -60 42 51.718989987   12.33 10.20 11.66   LBV 118 0
22 * y Car sg* 11 12 36.0128669807 -60 19 03.449914755 5.20 5.17 4.62 4.07 3.71 A5Iae: 89 0
23 V* II Hya LP* 11 48 45.0831243 -26 44 59.203936 8.38 6.71 5.11     M4+III 94 0
24 HD 105071 * 12 05 53.6200142443 -65 32 48.754487986 6.05 6.436 6.303     B8Ia 44 0
25 HD 106343 s*b 12 14 16.9255009123 -64 24 30.669505386 5.58 6.292 6.235     B1.5Ia 84 0
26 HD 109867 s*b 12 38 52.3586203902 -67 11 34.977744461 5.5 6.263 6.265 7.45   B0.5/1Iab 93 0
27 HD 115842 Em* 13 20 48.3389216362 -55 48 02.482627552 5.70 6.39 6.09 5.77 5.52 B0.5Ia/ab 143 0
28 HD 122879 V* 14 06 25.1577457205 -59 42 57.253857893 5.90 6.64 6.50 6.33 6.18 B0Ia 161 1
29 HD 148688 s*b 16 31 41.7695375461 -41 49 01.729591907 5.16 5.78 5.39 5.05 4.70 B1Iaeqp 154 0
30 * zet01 Sco s*b 16 53 59.7270104119 -42 21 43.313745214 4.80 5.31 4.79 4.32 3.86 B1Ia-0ek 351 0
31 HD 160529 sg* 17 41 59.0257256544 -33 30 13.702939546 8.17 7.87 6.66 5.50 4.51 A2Ia 188 1
32 HD 183143 s*b 19 27 26.5636908636 +18 17 45.191198361 8.25 8.08 6.86 5.74 4.79 B6Ia 413 0
33 * P Cyg s*b 20 17 47.2020844 +38 01 58.552724 4.66 5.24 4.82 4.28 4.02 B1-2Ia-0ep 1140 1

    Equat.    Gal    SGal    Ecl

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2021.02.26-17:41:35

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