The binary millisecond pulsar PSR J1023+0038-II. Optical spectroscopy
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 spec...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/173387 |
| Acceso en línea: | https://hdl.handle.net/2117/173387 https://dx.doi.org/10.1093/mnras/stz1652 |
| Access Level: | acceso abierto |
| Palabra clave: | Stars Binaries: close Stars: fundamental parameters Stars: individual: PSR J1023+0038 Stars: neutron X-rays: binaries Neutrons Estels Àrees temàtiques de la UPC::Física::Astronomia i astrofísica |
| Sumario: | 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. |
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