J/A+A/713/A309ivo://CDS.VizieR/J/A+A/713/A309CDSMessa M.M.Baglio M.C.D'Avanzo P.Illiano G.Coti Zelati F.,Alabarta K.de Martino D.Hu Y.-D.Miraval Zanon A.Reguitti A.,Campana S.2026-09-23T07:51:55Z2026-09-23T08:50:03ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frx-ray-binary-starsvisible-astronomyspectroscopyTransitional millisecond pulsars (tMSPs) are neutron-star binaries that switch between rotation-powered and accretion-powered states, providing a key link between low-mass X-ray binaries and millisecond radio pulsars. In their sub-luminous disc state, these systems exhibit complex variability whose origin remains under debate. We present high time-resolution optical spectroscopic observations of the tMSP PSR J1023+0038 obtained during its sub-luminous disc state. Our dataset covers for the first time a full orbital cycle at minute-timescale cadence. We detect significant variability in the main properties of the optical emission lines, including the equivalent width (EW) and full width at half maximum (FWHM), on timescales of minutes. A comparison between the temporal evolution of these quantities reveals indications of correlated behaviour, with some FWHM minima coinciding with a decrease in EW. This may point to episodes of matter ejection from the inner regions of the accretion disc, possibly associated with switches to low modes. Doppler tomography of the Halpha and Hbeta emission lines indicates possible asymmetric emission structures, consistent with a scenario in which part of the accreting material is expelled from the system. In addition, the optical continuum shows variability consistent with a possible orbital modulation associated with the irradiated companion star, although its characterisation is limited by the observing conditions. Our results provide new constraints on the short-timescale behaviour of tMSPs in the sub-luminous disc state and support scenarios in which accretion and outflow processes coexist. Further multiwavelength observations, particularly with simultaneous X-ray coverage, will be crucial to establish a direct link between the observed optical variability and the switches between the high and low modes.2026A&A...713A.309Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/713/A309CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/591/A101 : PSR J1023+0038 + XSS J12270-4859 VRi polarimetryJ/A+A/631/A104 : PSR J1023+0038 VLT, XM and Swift observations (Baglio+, 2019)J/A+A/690/A344 : Optical spectra of PSR J1023+0038 (Messa+, 2024)J/ApJ/960/20 : Flare param. from K2 + TESS data of PSR J1023+0038J/A+A/709/A170 : PSR J1023+0038 Nov 14-15 2017 photon lists (Karpov+, 2026)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/713/A309https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/713/A309http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/713/A309https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/713/A309https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/713/A309http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/713/A309GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayOpticaldefaultJ/A+A/713/A309/obslogObservation time for each spectrumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintspShow the spectrummeta.ref.urlcharFileNameName of the spectrum file in subdirectory spmeta.id;meta.filecharObsDateObservation datetime.epoch;obsnullableTimeUTC timehtime.epochdouble