Title:
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The binary millisecond pulsar PSR J1023+0038-II. Optical spectroscopy
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Author:
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Shahbaz, T.; Linares Alegret, Manuel; Rodríguez Gil, Pablo; Casares, Jorge
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Other authors:
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Universitat Politècnica de Catalunya. Departament de Física; Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica |
Abstract:
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We present time-resolved optical spectroscopy of the ‘redback’ binary millisecond pulsar system PSR¿J1023+0038 during both its radio pulsar (2009) and accretion disc states (2014 and 2016). We provide observational evidence for the companion star being heated during the disc state. We observe a spectral type change along the orbit, from ~G5 to ~F6 at the secondary star’s superior and inferior conjunction, respectively, and find that the corresponding irradiating luminosity can be powered by the high-energy accretion luminosity or the spin-down luminosity of the neutron star. We determine the secondary star’s radial velocity semi-amplitude from the metallic (primarily Fe and Ca) and Ha absorption lines during these different states. The metallic and Ha radial velocity semi-amplitude determined from the 2009 pulsar-state observations allows us to constrain the secondary star’s true radial velocity K2 = 276.3 ± 5.6 ¿km¿s-1 and the binary mass ratio q = 0.137 ± 0.003. By comparing the observed metallic and Ha absorption-line radial velocity semi-amplitudes with model predictions, we can explain the observed semi-amplitude changes during the pulsar state and during the pulsar/disc-state transition as being due to different amounts of heating and the presence of an accretion disc, respectively. |
Subject(s):
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-Àrees temàtiques de la UPC::Física::Astronomia i astrofísica -Stars -Binaries: close -Stars: fundamental parameters -Stars: individual: PSR J1023+0038 -Stars: neutron -X-rays: binaries -Neutrons -Estels |
Rights:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
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Article - Published version Article |
Published by:
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Oxford University Press
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