Reference : B fields in OB stars (BOB). Detection of a strong magnetic field in the O9.7 V star H...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/189711
B fields in OB stars (BOB). Detection of a strong magnetic field in the O9.7 V star HD 54879
English
Castro, N. [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany]
Fossati, L. [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany]
Hubrig, S. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482, Potsdam, Germany]
Simón-Díaz, S. [Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain; Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain]
Schöller, M. [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching bei München, Germany]
Ilyin, I. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482, Potsdam, Germany]
Carrol, T. A. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482, Potsdam, Germany]
Langer, N. [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany]
Morel, Thierry mailto [Université de Liège > > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Schneider, F. R. N. [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany; Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK]
Przybilla, N. [Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstr. 25/8, 6020, Innsbruck, Austria]
Herrero, A. [Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain; Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain]
de Koter, A. [Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ, Amsterdam, The Netherlands; Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Oskinova, L. M. [Institute for Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany]
Reisenegger, A. [Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile]
Sana, H. [European Space Agency, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218, USA]
BOB Collaboration [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121, Bonn, Germany)]
1-Sep-2015
Astronomy and Astrophysics
581
81
Yes
International
[en] stars: atmospheres ; stars: evolution ; stars: magnetic field ; stars: massive ; stars: individual: HD 54879
[en] The number of magnetic stars detected among massive stars is small; nevertheless, the role played by the magnetic field in stellar evolution cannot be disregarded. Links between line profile variability, enhancements/depletions of surface chemical abundances, and magnetic fields have been identified for low-mass B-stars, but for the O-type domain this is almost unexplored. Based on FORS 2 and HARPS spectropolarimetric data, we present the first detection of a magnetic field in HD 54879, a single slowly rotating O9.7 V star. Using two independent and different techniques we obtained the firm detection of a surface average longitudinal magnetic field with a maximum amplitude of about 600 G, in modulus. A quantitative spectroscopic analysis of the star with the stellar atmosphere code fastwind results in an effective temperature and a surface gravity of 33 000 ± 1000 K and 4.0 ± 0.1 dex. The abundances of carbon, nitrogen, oxygen, silicon, and magnesium are found to be slightly lower than solar, but compatible within the errors. We investigate line-profile variability in HD 54879 by complementing our spectra with spectroscopic data from other recent OB-star surveys. The photospheric lines remain constant in shape between 2009 and 2014, although Hα shows a variable emission. The Hα emission is too strong for a standard O9.7 V and is probably linked to the magnetic field and the presence of circumstellar material. Its normal chemical composition and the absence of photospheric line profile variations make HD 54879 the most strongly magnetic, non-variable single O-star detected to date. Based on observations made with ESO telescopes at the La Silla and Paranal observatories under programme ID 191.D-0255(C, F).Appendix A is available in electronic form at <A href="http://www.aanda.org/10.1051/0004-6361/201425354/olm">http://www.aanda.org</A>
http://hdl.handle.net/2268/189711
10.1051/0004-6361/201425354
http://adsabs.harvard.edu/abs/2015A%26A...581A..81C

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