Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR2. (arXiv:1905.05815v1 [astro-ph.SR])

Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR2. (arXiv:1905.05815v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chene_A/0/1/0/all/0/1">A.-N. Chen&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+St_Louis_N/0/1/0/all/0/1">N. St-Louis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moffat_A/0/1/0/all/0/1">A. F. J. Moffat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schnurr_O/0/1/0/all/0/1">O. Schnurr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crowther_P/0/1/0/all/0/1">P. A. Crowther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wade_G/0/1/0/all/0/1">G. A. Wade</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Richardson_N/0/1/0/all/0/1">N. D. Richardson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baranec_C/0/1/0/all/0/1">C. Baranec</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ziegler_C/0/1/0/all/0/1">C. A. Ziegler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Law_N/0/1/0/all/0/1">N. M. Law</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Riddle_R/0/1/0/all/0/1">R. Riddle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rate_G/0/1/0/all/0/1">G. A. Rate</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Artigau_E/0/1/0/all/0/1">&#xc9;. Artigau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alecian_E/0/1/0/all/0/1">E. Alecian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+collaboration_BinaMIcS/0/1/0/all/0/1">BinaMIcS collaboration</a>

The hot WN star WR2 (HD6327) has been claimed to have many singular
characteristics. To explain its unusually rounded and relatively weak emission
line profiles, it has been proposed that WR2 is rotating close to break-up with
a magnetically confined wind. Alternatively, the line profiles could be
explained by the dilution of WR2’s spectrum by that of a companion. In this
paper, we present a study of WR2 using near-infrared AO imaging and optical
spectroscopy and polarimetry. Our spectra reveal the presence of weak
photospheric absorption lines from a ~B2.5-4V companion, which however
contributes only ~5-10% to the total light, suggesting that the companion is a
background object. Therefore, its flux cannot be causing any significant
dilution of the WR star’s emission lines. The absence of intrinsic linear
continuum polarization from WR2 does not support the proposed fast rotation.
Our Stokes V spectrum was not of sufficient quality to test the presence of a
moderately strong organized magnetic field but our new modelling indicates that
to confine the wind the putative magnetic field must be significantly stronger
than was previously suggested sufficiently strong as to make its presence
implausible.

The hot WN star WR2 (HD6327) has been claimed to have many singular
characteristics. To explain its unusually rounded and relatively weak emission
line profiles, it has been proposed that WR2 is rotating close to break-up with
a magnetically confined wind. Alternatively, the line profiles could be
explained by the dilution of WR2’s spectrum by that of a companion. In this
paper, we present a study of WR2 using near-infrared AO imaging and optical
spectroscopy and polarimetry. Our spectra reveal the presence of weak
photospheric absorption lines from a ~B2.5-4V companion, which however
contributes only ~5-10% to the total light, suggesting that the companion is a
background object. Therefore, its flux cannot be causing any significant
dilution of the WR star’s emission lines. The absence of intrinsic linear
continuum polarization from WR2 does not support the proposed fast rotation.
Our Stokes V spectrum was not of sufficient quality to test the presence of a
moderately strong organized magnetic field but our new modelling indicates that
to confine the wind the putative magnetic field must be significantly stronger
than was previously suggested sufficiently strong as to make its presence
implausible.

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