J/ApJ/965/L10ivo://CDS.VizieR/J/ApJ/965/L10CDSGaudin T.M.Kennea J.A.Coe M.J.Monageng I.M.Udalski A.,Townsend L.J.Buckley D.A.H.Evans P.A.2026-09-08T09:36:41Z2026-09-08T10:01:17ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsx-ray-binary-starsphotometrybe-starsvisible-astronomyspectroscopyWe report on the discovery of Swift J010902.6-723710, a rare eclipsing Be/X-ray Binary system by the Swift SMC Survey (S-CUBED). Swift J010902.6-723710 was discovered via weekly S-CUBED monitoring observations when it was observed to enter a state of X-ray outburst on 2023 October 10. X-ray emission was found to be modulated by a 182s period. Optical spectroscopy is used to confirm the presence of a highly inclined circumstellar disk surrounding a B0-0.5Ve optical companion. Historical UV and IR photometry is then used to identify strong eclipse-like features reoccurring in both light curves with a 60.623 day period, which is adopted as the orbital period of the system. Eclipsing behavior is found to be the result of a large accretion disk surrounding the neutron star. Eclipses are produced when the disk passes in front of the OBe companion, blocking light from both the stellar surface and circumstellar disk. This is only the third Be/X-ray binary to have confirmed eclipses. We note that this rare behavior provides an important opportunity to constrain the physical parameters of a Be/X-ray binary with greater accuracy than is possible in noneclipsing systems.2024ApJ...965L..10Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/965/L10CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/353/601 : 2dF survey of the Small Magellanic Cloud (Evans+, 2004)J/AJ/127/1531 : Star formation history of SMC (Harris+, 2004)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)J/A+A/574/A33 : BVRI photometry of high-mass X-ray binaries (Reig+, 2015)J/A+A/586/A81 : High-mass X-ray binaries in the SMC (Haberl+, 2016)J/ApJ/868/47 : 1st year of the Swift SMC Survey (S-CUBED) (Kennea+, 2018)J/ApJ/904/13 : Radial velocity for 10 giant EBs (Graczyk+, 2020)J/AcA/74/241 : OGLE-IV MC eclipsing & ellipsoidal binaries (Glowacki+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/965/L10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/965/L10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/965/L10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/965/L10https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/965/L10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/965/L10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayOpticaldefaultJ/ApJ/965/L10/fig1XRT light curve for Swift J010902.6-723710 from August 2023 to present, combining data from S-CUBED observations and follow-up TOOsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeObservation type (1)meta.id;meta.datasetcharMJD[60129.9/60353.11] Modified Julian Datedtime.epochdoubleE_MJD[0.0002/0.31] Upper uncertainty in MJDdstat.error;stat.max;time.epochdoublee_MJDLower uncertainty in MJDdstat.error;stat.min;time.epochdoublel_LumUpper limit flag on Lummeta.code.errorcharLum[5.8e+35/1.6e+37] The 0.3-10keV X-ray luminosity in erg/s (2)1e-07Wphys.luminosity;em.X-raydoubleE_Lum[/3.25e+36]? Upper uncertainty in Lum1e-07Wstat.error;stat.max;phys.luminositydoublenullablee_Lum[/2.71e+36]? Lower uncertainty in Lum1e-07Wstat.error;stat.min;phys.luminositydoublenullableJ/ApJ/965/L10/fig3OGLE IV, Swift UVOT, and Swift XRT light curves for Swift J010902.6-723710e_mag? Lower uncertainty in magmagstat.error;stat.min;phot.magdoublenullablel_CRUpper limit flag on CRmeta.code.errorcharCR[0.012/0.46]? Observed XRT count rate from Sourcephot.count;em.X-raydoublenullableE_CR[0.003/0.08]? Upper uncertainty in CRstat.error;stat.max;phot.countdoublenullablee_CR? Lower uncertainty in CRstat.error;stat.min;phot.countdoublenullableSourceData source (1)meta.id;meta.datasetcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[5346.93/60305] Modified Julian Date (MJD=JD-2400000.5 for XRT and UVOT; or JD-2450000 for OGLE)dtime.epochdoubleE_MJD[0/0.17] Upper uncertainty in MJDdstat.error;stat.max;time.epochdoublee_MJDLower uncertainty in MJDdstat.error;stat.min;time.epochdoublemag[13.7/17.1]? Observed magnitude from Sourcemagphot.magdoublenullableE_mag[0.003/0.1]? Upper uncertainty in magmagstat.error;stat.max;phot.magdoublenullableJ/ApJ/965/L10/fig4The whole and de-trended OGLE data set covering 26 yearsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeData type (1)meta.id;meta.datasetcharJD[627.92/10248.7] Julian Date of observation; JD-2450000dtime.epochdoublemag[-0.2/17.11] OGLE IV I band magnitude of Typemagphot.magfloate_mag[0/0.02] Uncertainty in mag (2)magstat.error;phot.magfloatJ/ApJ/965/L10/fig8The SALT spectral observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[60251.88/60280.85] Modified Julian Date of the observation (1)dtime.epochdoubleindexedlambda[3843.56/7263.62] Wavelength; Angstroms0.1nmem.wlfloatNFlux[0.57/1.75] Normalized fluxphot.flux;arith.ratiofloat