J/ApJ/940/165ivo://CDS.VizieR/J/ApJ/940/165doi:10.26093/cds/vizier.19400165CDSYuan H.Wang S.Bai Z.Wang Y.Dong Y.Wang M.Yu S.Zhao Y.,Chu Y.Liu J.Zhang H.2025-02-24T20:13:35Z2024-12-04T13:26:54ZCDS support team

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

cds-question@unistra.frradial-velocityvisible-astronomyspectroscopyneutron-starsmultiple-starsWe report the discovery of one possible neutron star binary (P_orb_=0.8666d) by using LAMOST low-resolution spectroscopic data. The visible companion is a late A-type dwarf (Teff=7900+/-200K; logg=4.3+/-0.2; M=1.7+/-0.1M_{sun}_; R=1.7+/-0.2R_{sun}_) at a distance of 1.11+/-0.03kpc. No double-lined feature can be seen from the Gran Telescopio Canarias/HORuS high-resolution spectra; thus the radial-velocity variation indicates an invisible object hiding in the binary. The system's optical light curves show clear ellipsoidal variability, suggesting that the visible companion is tidal distorted. By fitting the multiband light curves with the eclipsing light-curve (ELC) code and the Wilson-Devinney (WD) code, we constrain the mass of the invisible star to be 1.1-1.3M_{sun}_. Spectral disentangling shows no additional component with optical absorption spectra, supporting the idea that the system contains one compact object. No X-ray or UV emission is detected in the ROSAT archive observations. Therefore, we suspect the invisible object is more likely a neutron star rather than a white dwarf. Our finding suggests the ability of LAMOST spectroscopic survey to discover X-ray-quiescent compact objects.2022ApJ...940..165Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/940/165CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)I/284 : The USNO-B1.0 Catalog (Monet+ 2003)I/340 : UCAC5 Catalogue (Zacharias+ 2017)V/156 : LAMOST DR7 catalogs (Luo+, 2019)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/ApJ/809/25 : Stellar & planet data for K2 candidates (Montet+, 2015)J/A+A/588/A103 : 2nd ROSAT all-sky survey (2RXS) source cat. (Boller+, 2016)J/MNRAS/479/5491 : Absolute parameters of 509 main-sequence stars (Eker+, 2018)J/other/RAA/19.64 : LAMOST sp. binaries & variable stars (Qian+, 2019)J/ApJS/249/18 : The ZTF catalog of periodic variable stars (Chen+, 2020)J/ApJS/251/15 : LAMOST-Kepler/K2 survey (LK-MRS) 1st year obs. (Zong+, 2020)J/other/RAA/21.292 : LAMOST Time-Domain survey, first results (Wang+, 2021)J/A+A/659/A95 : Survey of Surveys. I. Radial velocities (Tsantaki+, 2022)J/ApJS/259/11 : LAMOST variable sources based on ZTF phot. (Xu+, 2022)J/ApJS/266/14 : Am stars selected in LAMOST DR8-DR10 (Tian+, 2023)J/ApJS/271/4 : Rotational velocities for LAMOST DR9 stars (Zuo+, 2024)J/ApJS/272/1 : Periodic variable stars from LAMOST DR9 (Qiao+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/940/165https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/940/165http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/940/165https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/940/165https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/940/165http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/940/165GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/940/165/table1Barycentric-corrected RV values from LAMOST low-resolution observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[57085.5/58456.8] Barycentric Julian Date, BJD-2400000.5dtime.epochdoubleBRV[-99/154] Barycentric-corrected radial velocitykm/sspect.dopplerVelocfloate_BRV[7.3/11] Uncertainty in BRVkm/sstat.error;spect.dopplerVelocfloatJ/ApJ/940/165/table2Barycentric-corrected (B- and R-band) RV values from LAMOST medium resolution observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[59236.5/59264.6] Barycentric Julian Date, BJD-2400000.5dtime.epochdoubleBRVb[-94/30] Barycentric-corrected radial velocity, B-bandkm/sspect.dopplerVeloc;em.opt.Bfloate_BRVb[1/4.3] Uncertainty in BRVbkm/sstat.error;spect.dopplerVeloc;em.opt.BfloatBRVr[-90/28] Barycentric-corrected radial velocity, R-bandkm/sspect.dopplerVeloc;em.opt.Rfloate_BRVr[1.3/2.4] Uncertainty in BRVrkm/sstat.error;spect.dopplerVeloc;em.opt.RfloatJ/ApJ/940/165/table3Barycentric-corrected RV values from HORuS observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[58809.2/58814.1] Barycentric Julian Date, BJD-2400000.5dtime.epochdoubleBRV[-87/134] Barycentric-corrected radial velocitykm/sspect.dopplerVelocfloate_BRV[4.3/4.6] Uncertainty in BRVkm/sstat.error;spect.dopplerVelocfloat