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A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY, delta ORIONIS Aa. II. X-RAY VARIABILITY

  • We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the delta Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of approximate to 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 is is confirmed, with a maximum amplitude of about +/- 15% within a single approximate to 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S XV, Si XIII, and Ne IX. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi = 0.0We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the delta Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of approximate to 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 is is confirmed, with a maximum amplitude of about +/- 15% within a single approximate to 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S XV, Si XIII, and Ne IX. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi = 0.0 when the secondary delta Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind-wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability.show moreshow less

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Metadaten
Author:Joy Nichols, David P. Huenemoerder, Michael F. Corcoran, Wayne Waldron, Yael Naze, Andy M. T. Pollock, Anthony F. J. Moffat, Jennifer Lauer, Tomer ShenarORCiDGND, Christopher M. P. Russell, Noel D. Richardson, Herbert Pablo, Nancy Remage Evans, Kenji Hamaguchi, Theodore Gull, Wolf-Rainer HamannORCiDGND, Lida Oskinova, Rosina Ignace, Jennifer L. Hoffman, Karen Tabetha Hole, Jamie R. Lomax
DOI:https://doi.org/10.1088/0004-637X/809/2/133
ISSN:0004-637X (print)
ISSN:1538-4357 (online)
Parent Title (English):The astrophysical journal : an international review of spectroscopy and astronomical physics
Publisher:IOP Publ. Ltd.
Place of publication:Bristol
Document Type:Article
Language:English
Year of first Publication:2015
Year of Completion:2015
Release Date:2017/03/27
Tag:binaries: close; binaries: eclipsing; stars: individual ([HD 36486]delta Ori A)
Volume:809
Issue:2
Pagenumber:21
Funder:National Aeronautics and Space Administration through Chandra Award [GO3-14015A, G03-14015E, GO3-14015G]; National Aeronautics Space Administration [NAS8-03060]; NASA through the Smithsonian Astrophysical Observatory [SV3-73016]; Fonds National de la Recherche Scientifique (Belgium); Communaute Francaise de Belgique; PRODEX XMM and Integral contracts; Action de Recherche Concertee (CFWB-Academie Wallonie Europe); NSRC (Canada); FRQNT (Quebec); CRAQ (Centre de Recherche en Astrophysique du Quebec) fellowship; DLR [50 OR 1302]; Chandra X-ray Center NASA [NAS8-03060]; NASA [NNX13AF40G]; NSF [AST-0807477]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
Peer Review:Referiert