The binary millisecond pulsar PSR J1023+0038 -- II. Optical spectroscopy

Abstract

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 Halpha absorption lines during these different states. The metallic and Halpha 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 and the binary mass ratio q=0.137+/-0.003. By comparing the observed metallic and Halpha 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.

16 pages, 13 figures. Accepted for publication in MNRAS

References in corpus (8)

• A Radio Pulsar/X-ray Binary Link
• Optical spectroscopy and demographics of redback millisecond pulsar binaries
• X-ray states of redback millisecond pulsars
• Timing Observations of PSR J1023+0038 During a Low-Mass X-ray Binary State
• NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038
• SDSS J102347.6+003841: A Millisecond Radio Pulsar Binary That Had A Hot Disk During 2000-2001
• Properties of the redback millisecond pulsar binary 3FGL J0212.1+5320
• Variable polarisation and Doppler tomography of PSR J1023+0038 - Evidence for the magnetic propeller during flaring?

Cited by in corpus (5)

• Optical photometry of two transitional millisecond pulsars in the radio pulsar state
• The MAVERIC Survey: Simultaneous Chandra and VLA observations of the transitional millisecond pulsar candidate NGC 6652B
• The peculiar chemical abundance of the transitional millisecond pulsar PSR J1023+0038 -- Li enhancement
• X-ray variability of transitional millisecond pulsars: a faint, stable and fluctuating disk
• Periodicity search for Pulsar Binaries with TESS