A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Δ Orionis Aa. IV. A Multiwavelength, Non-LTE Spectroscopic Analysis
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http://hdl.handle.net/10045/59172
Títol: | A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Δ Orionis Aa. IV. A Multiwavelength, Non-LTE Spectroscopic Analysis |
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Autors: | Shenar, Tomer | Oskinova, Lidia M. | Hamann, Wolf-Rainer | Corcoran, Michael F. | Moffat, Anthony F.J. | Pablo, Herbert | Richardson, Noel D. | Waldron, Wayne L. | Huenemoerder, David P. | Maíz Apellániz, Jesús | Nichols, Joy S. | Todt, Helge | Nazé, Yaël | Hoffman, Jennifer L. | Pollock, A.M.T. | Negueruela, Ignacio |
Grups d'investigació o GITE: | Astrofísica Estelar (AE) |
Centre, Departament o Servei: | Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal |
Paraules clau: | Binaries: close | Binaries: eclipsing | Stars: early-type | Stars: individual ([HD 36486]δOri A) | X-rays: stars |
Àrees de coneixement: | Astronomía y Astrofísica |
Data de publicació: | 18-d’agost-2015 |
Editor: | IOP Publishing |
Citació bibliogràfica: | The Astrophysical Journal. 2015, 809:135 (20pp). doi:10.1088/0004-637X/809/2/135 |
Resum: | Eclipsing systems of massive stars allow one to explore the properties of their components in great detail. We perform a multi-wavelength, non-LTE analysis of the three components of the massive multiple system δ Ori A, focusing on the fundamental stellar properties, stellar winds, and X-ray characteristics of the system. The primary's distance-independent parameters turn out to be characteristic for its spectral type (O9.5 II), but usage of the Hipparcos parallax yields surprisingly low values for the mass, radius, and luminosity. Consistent values follow only if δ Ori lies at about twice the Hipparcos distance, in the vicinity of the σ-Orionis cluster. The primary and tertiary dominate the spectrum and leave the secondary only marginally detectable. We estimate the V-band magnitude difference between primary and secondary to be ${\rm{\Delta }}V\approx 2\buildrel{\rm{m}}\over{.} 8$. The inferred parameters suggest that the secondary is an early B-type dwarf (≈B1 V), while the tertiary is an early B-type subgiant (≈B0 IV). We find evidence for rapid turbulent velocities (~200 km s−1) and wind inhomogeneities, partially optically thick, in the primary's wind. The bulk of the X-ray emission likely emerges from the primary's stellar wind ($\mathrm{log}{L}_{{\rm{X}}}/{L}_{\mathrm{Bol}}\approx -6.85$), initiating close to the stellar surface at ${R}_{0}\sim 1.1\;{R}_{*}$. Accounting for clumping, the mass-loss rate of the primary is found to be $\mathrm{log}\dot{M}\approx -6.4$ $({M}_{\odot }\;{\mathrm{yr}}^{-1})$, which agrees with hydrodynamic predictions, and provides a consistent picture along the X-ray, UV, optical, and radio spectral domains. |
Patrocinadors: | T.S. is grateful for financial support from the Leibniz Graduate School for Quantitative Spectroscopy in Astrophysics, a joint project of the Leibniz Institute for Astrophysics Potsdam (AIP) and the institute of Physics and Astronomy of the University of Potsdam. L.M.O. acknowledges support from DLR grant 50 OR 1302. M.F.C., J.S.N., and W.L.W. are grateful for support via Chandra grants GO3-14015A and GO3-14015E. A.F.J.M. acknowledges financial aid from NSERC (Canada) and FRQNT (Quebec). J.M.A. acknowledges support from (a) the Spanish Government Ministerio de Economía y Competitividad (MINECO) through grants AYA2010-15 081 and AYA2010-17 631 and (b) the Consejería de Educación of the Junta de Andalucía through grant P08-TIC-4075. Caballero N.D.R. gratefully acknowledges his Centre du Recherche en Astrophysique du Québec (CRAQ) fellowship. Y.N. acknowledges support from the Fonds National de la Recherche Scientifique (Belgium), the Communauté Française de Belgique, the PRODEX XMM and Integral contracts, and the “Action de Recherche Concertée” (CFWB-Académie Wallonie Europe). J.L.H. acknowledges support from NASA award NNX13AF40G and NSF award AST-0807477. I.N. is supported by the Spanish Mineco under grant AYA2012-39364-C02-01/02, and the European Union. |
URI: | http://hdl.handle.net/10045/59172 |
ISSN: | 0004-637X (Print) | 1538-4357 (Online) |
DOI: | 10.1088/0004-637X/809/2/135 |
Idioma: | eng |
Tipus: | info:eu-repo/semantics/article |
Drets: | © 2015. The American Astronomical Society |
Revisió científica: | si |
Versió de l'editor: | http://dx.doi.org/10.1088/0004-637X/809/2/135 |
Apareix a la col·lecció: | INV - Astrofísica Estelar - Artículos de Revistas |
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2015_Shenar_etal_ApJ.pdf | 3,44 MB | Adobe PDF | Obrir Vista prèvia | |
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