2017A&A...598A..85S


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.10CEST02:11:15

2017A&A...598A..85S - Astronomy and Astrophysics, volume 598A, 85-85 (2017/2-1)

The Tarantula Massive Binary Monitoring. II. First SB2 orbital and spectroscopic analysis for the Wolf-Rayet binary R145.

SHENAR T., RICHARDSON N.D., SABLOWSKI D.P., HAINICH R., SANA H., MOFFAT A.F.J., TODT H., HAMANN W.-R., OSKINOVA L.M., SANDER A., TRAMPER F., LANGER N., BONANOS A.Z., DE MINK S.E., GRAFENER G., CROWTHER P.A., VINK J.S., ALMEIDA L.A., DE KOTER A., BARBA R., HERRERO A. and ULACZYK K.

Abstract (from CDS):

We present the first SB2 orbital solution and disentanglement of the massive Wolf-Rayet binary R145 (P=159d) located in the Large Magellanic Cloud. The primary was claimed to have a stellar mass greater than 300M, making it a candidate for being the most massive star known to date. While the primary is a known late-type, H-rich Wolf-Rayet star (WN6h), the secondary has so far not been unambiguously detected. Using moderate-resolution spectra, we are able to derive accurate radial velocities for both components. By performing simultaneous orbital and polarimetric analyses, we derive the complete set of orbital parameters, including the inclination. The spectra are disentangled and spectroscopically analyzed, and an analysis of the wind-wind collision zone is conducted. The disentangled spectra and our models are consistent with a WN6h type for the primary and suggest that the secondary is an O3.5 If*/WN7 type star. We derive a high eccentricity of e=0.78 and minimum masses of M1sin3i~=M2sin3i=13±2M, with q=M2/M1=1.01±0.07. An analysis of emission excess stemming from a wind-wind collision yields an inclination similar to that obtained from polarimetry (i=39±6°). Our analysis thus implies M1=53+40–20 and M2=54+40–20M, excluding M1>300M. A detailed comparison with evolution tracks calculated for single and binary stars together with the high eccentricity suggests that the components of the system underwent quasi-homogeneous evolution and avoided mass-transfer. This scenario would suggest current masses of ~=80M and initial masses of Mi,1~=105 and Mi,2~=90M, consistent with the upper limits of our derived orbital masses, and would imply an age of ~=2.2Myr.

Abstract Copyright: © ESO, 2017

Journal keyword(s): binaries: spectroscopic - stars: Wolf-Rayet - stars: massive - Magellanic Clouds - stars: individual: R 145 - stars: atmospheres

VizieR on-line data: <Available at CDS (J/A+A/598/A85): table.dat>

Simbad objects: 18

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Number of rows : 18

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 HD 5980 WR* 00 59 26.5847969465 -72 09 53.927725716   11.13 11.31   11.029 WN4+O7I: 359 1
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5669 1
3 LHA 120-S 28 WR* 05 21 57.6943623106 -65 49 00.226696063 12.395 13.12 13.32 13.62 13.295 WN6h 42 0
4 Brey 25 WR* 05 22 04.4095841528 -67 59 06.779107874 14.589 15.326 15.207   14.993 WN4b 35 0
5 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14832 1
6 NAME 30 Dor Region reg 05 38.0 -69 06           ~ 178 0
7 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1039 2
8 NGC 2070 Cl* 05 38 42 -69 06.0     7.25     ~ 328 1
9 RMC 136 Cl* 05 38 42.396 -69 06 03.36           ~ 1736 1
10 UCAC4 105-014417 WR* 05 38 55.5218836143 -69 04 26.810760074   16.66 16.08   14.89 WN5h 49 0
11 HD 269928 WR* 05 38 57.0668705166 -69 06 05.660972436   12.02 11.94 12.00 11.58 WN6/7 119 0
12 V* V712 Car bL* 10 23 58.0120989646 -57 45 48.938103165 15.466 15.473 13.5 12.6   O3If*/WN6+O3If*/WN6 147 1
13 WR 21a WR* 10 25 56.5023591737 -57 48 43.517827393     12.67     O2If*/WN5 80 0
14 HD 92740 WR* 10 41 17.5154230335 -59 40 36.897706569 5.68 6.50 6.42 7.38   WN7h+O9III-V 381 0
15 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2201 0
16 Cl* NGC 3603 BLW A1 WR* 11 15 07.31 -61 15 38.4   12.32 11.18     WN6h 59 0
17 Mrk 51 GiG 12 24 14.5321232503 +04 13 33.588515642   15.2       ~ 40 0
18 NAME Local Group GrG ~ ~           ~ 6973 0

    Equat.    Gal    SGal    Ecl

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2020.07.10-02:11:15

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