The binary millisecond pulsar PSR J1023+0038 – II. Optical spectroscopy
Jun 11, 201915 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 488 (2019) 1, 198-212
- Published: Sep 1, 2019
e-Print:
- 1906.04524 [astro-ph.SR]
DOI:
- 10.1093/mnras/stz1652 (publication)
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Abstract: (Oxford University Press)
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 Hα absorption lines during these different states. The metallic and Hα radial velocity semi-amplitude determined from the 2009 pulsar-state observations allows us to constrain the secondary star’s true radial velocity K_2 = 276.3 ± 5.6 km s^−1 and the binary mass ratio q = 0.137 ± 0.003. By comparing the observed metallic and Hα 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.Note:
- 16 pages, 13 figures. Accepted for publication in MNRAS
- binaries: close
- stars: fundamental parameters
- stars: individual: PSR J1023+0038
- stars: neutron
- X-rays: binaries
References(64)
Figures(14)