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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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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. ; Ulaczyk, K.
Total Authors: 22
Document type: Journal article
Source: Astronomy & Astrophysics; v. 598, FEB 2017.
Web of Science Citations: 13

We present the first SB2 orbital solution and disentanglement of the massive Wolf-Rayet binary R145 (P = 159 d) located in the Large Magellanic Cloud. The primary was claimed to have a stellar mass greater than 300 M-circle dot, 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 M-1 sin(3) i approximate to M-2 sin(3) i = 13 +/- 2 M-circle dot, with q = M-2/M-1 = 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 degrees). Our analysis thus implies M-1 = 53(-20)(+40) and M2 = 54(-20)(+40) M-circle dot, excluding M-1 > 300 M-circle dot. 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 approximate to 80 M-circle dot and initial masses of M-i,M-1 approximate to 10(5) and M-i,M-2 approximate to 90 M-circle dot, consistent with the upper limits of our derived orbital masses, and would imply an age of approximate to 2.2 Myr. (AU)

FAPESP's process: 12/09716-6 - Accurate distances to young clusters through massive eclipsing binaries
Grantee:Leonardo Andrade de Almeida
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 13/18245-0 - Full spectroscopic orbital solutions for more than 100 massive binaries in the high-mass starburst region 30 Doradus
Grantee:Leonardo Andrade de Almeida
Support Opportunities: Scholarships abroad - Research Internship - Post-doctor