Discovery of the magnetic field of the B1/B2V star σ Lupi
Paper
Paper/Presentation Title | Discovery of the magnetic field of the B1/B2V star σ Lupi |
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Presentation Type | Paper |
Authors | Henrichs, H. F. (Author), Kolenberg, K. (Author), Plaggenborg, B. (Author), Marsden, S. C. (Author), Waite, I. A. (Author), Landstreet, J. (Author), Grunhut, J. (Author), Oksala, M. (Author) and Wade, G. (Author) |
Editors | Hoffman, Jennifer L., Bjorkman, Jon and Whitney, Barbara |
Journal or Proceedings Title | AIP Conference Proceedings |
ERA Conference ID | 60018 |
Journal Citation | 1429 (1), pp. 90-93 |
Number of Pages | 4 |
Year | 2012 |
Publisher | AIP Publishing |
Place of Publication | United States |
ISSN | 1551-7616 |
ISBN | 9780735410121 |
Digital Object Identifier (DOI) | https://doi.org/10.1063/1.3701907 |
Web Address (URL) of Paper | https://pubs.aip.org/aip/acp/article-abstract/1429/1/90/802659/Discovery-of-the-magnetic-field-of-the-B1-B2V-star?redirectedFrom=fulltext |
Web Address (URL) of Conference Proceedings | https://pubs.aip.org/aip/acp/issue/1429/1 |
Conference/Event | American Institute of Physics Conference (STARPOL 2011): Stellar Polarimetry: From Birth to Death |
American Institute of Physics (AIP) Conference | |
Event Details | American Institute of Physics Conference (STARPOL 2011): Stellar Polarimetry: From Birth to Death Event Date 27 to end of 30 Jun 2011 Event Location Madison, United States |
Event Details | American Institute of Physics (AIP) Conference AIP |
Abstract | In our search for new magnetic massive stars we use the strongest indirect indicator of a magnetic field in B stars, which is periodic variability of UV stellar wind lines occurring in a velocity range symmetric around zero. Our aim is to obtain follow-up spectropolarimetry to search for a magnetic field in magnetic candidate stars. We quantify UV wind line variability, and analyse its time behaviour. The B1/B2Vstar σ Lupi emerged as a new magnetic candidate star. AAT spectropolarimetric measurements with SEMPOL were obtained. The stellar wind line variations of σ Lupi are similar to what is known in magnetic B stars, but no periodicity could be determined. We detected a longitudinal magnetic field with varying strength and amplitude of about 100 G with error bars of typically 20 G, which supports an oblique magnetic-rotator configuration. The equivalent width variations of the UV lines, the magnetic and the optical line variations are consistent with the well-known photometric period of 3.02 days, which we identifywith the rotation period of the star. Additional observations with ESPaDOnS attached to the CFHT strongly confirmed this discovery, and allowed to determine a precise magnetic period. Further analysis revealed that σ Lupi is a helium-strong star, with an enhanced nitrogen abundance and an underabundance of carbon, and has a spotted surface. We conclude that σ Lupi is a magnetic oblique rotator, and is a He-strong star. It is the fourth B star for which a magnetic field is discovered from studying only its wind variability. Like in the other magnetic B stars the wind emission originates in the magnetic equator, with maximum emission occurring when a magnetic pole points towards the Earth. The 3.01819 d magnetic rotation period is consistent with the photometric period, with maximum light corresponding to maximum magnetic field. A full paper will be submitted to Astronomy & Astrophysics. |
Keywords | magnetic fields; massive stars; star spots; abundances |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
510404. Electronic and magnetic properties of condensed matter; superconductivity | |
510199. Astronomical sciences not elsewhere classified | |
Public Notes | This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conf. Proc. 1429, 90–93 (2012) and may be found at https://doi.org/10.1063/1.3701907 |
Byline Affiliations | University of Amsterdam, Netherlands |
University of Vienna, Austria | |
Anglo-Australian Observatory, Australia | |
Centre for Astronomy, Solar Radiation and Climate | |
University of Western Ontario, Canada | |
Queen's University, Canada | |
University of Delaware, United States | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q1603/discovery-of-the-magnetic-field-of-the-b1-b2v-star-lupi
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Henrichs_etal_AIP_v1429_PV.pdf | ||
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Henricks_etal_ACP_2012_PV.pdf | ||
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