J/MNRAS/489/1556ivo://CDS.VizieR/J/MNRAS/489/1556doi:10.26093/cds/vizier.74891556CDSBaran A.S.Telting J.H.Jeffery C.S.Ostensen R.H.Vos J.Reed M.D.,Vuckovic M.2024-08-20T20:12:34Z2023-02-10T12:13:41ZCDS support team

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

cds-question@unistra.frmultiple-starsorbitssubdwarf-starsvariable-starsradial-velocityeffective-temperaturevisible-astronomyspectroscopyWe present an analysis of two pulsating subdwarf B stars PHL 457 and EQ Psc observed during the K2 mission. The K2 light curves of both stars show variation consistent with irradiation of a cooler companion by the hot subdwarf. They also show higher frequency oscillations consistent with pulsation. Using new spectroscopic data, we measured the radial velocity, effective temperature, surface gravity, and helium abundance of both hot subdwarfs as a function of orbital phase. We confirm the previously published spectroscopic orbit of PHL 457, and present the first spectroscopic orbit of EQ Psc. The orbital periods are 0.313 and 0.801d, respectively. For EQ Psc, we find a strong correlation between T_eff_ and orbital phase, due to contribution of light from the irradiated companion. We calculated amplitude spectra, identified significant pulsation frequencies, and searched for multiplets and asymptotic period spacings. By means of multiplets and period spacing, we identified the degrees of several pulsation modes in each star. The g-mode multiplets indicate subsynchronous core rotation with periods of 4.6d (PHL 457) and 9.4d (EQ Psc). We made spectral energy distribution (SED) fits of PHL 457 and EQ Psc using available broad-band photometry and Gaia data. While the SED of PHL 457 shows no evidence of a cool companion, the SED for EQ Psc clearly shows an infrared (IR) access consistent with a secondary with a temperature of about 6800K and a radius of 0.23R_{sun}_. This is the first detection of an IR access in any sdB+dM binary.2019MNRAS.489.1556Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/489/1556CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/489/1556https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/489/1556http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/489/1556https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/489/1556https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/489/1556http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/489/1556GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/489/1556/table3 (Results of a circular orbital fit after folding the RVs of PHL 457 to orbital phase)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/1556/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/1556/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/1556/table3?GETtext/xml+votable180.050000true349.8517914-8.87720470.005555555555555556Cone search capability for table J/MNRAS/489/1556/table6 (Results of a circular orbital fit to the RVs of EQ PSc)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/1556/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/1556/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/1556/table6?GETtext/xml+votable180.050000true353.6442978-1.32692470.005555555555555556Cone search capability for table J/MNRAS/489/1556/table9 (sdB stars with orbital and rotation periods estimated)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/1556/table9?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/1556/table9?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/1556/table9?GETtext/xml+votable180.050000true349.8517914-8.87720470.0055555555555555566/4674 10024 14573 14585 14779 14825 14957 14961 15132 15148 17323 18766 25582 25845 26112 33097 43860https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/489/1556?format=asciiOpticaldefaultJ/MNRAS/489/1556/table1The ALFOSC RV data of PHL 457recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Datedtime.epochdoubleRVALFOSC Radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVError on RVkm/sstat.errorfloatS/NSignal to noise ratiostat.snrfloattexpExposure timestime.duration;obs.exposureintJ/MNRAS/489/1556/table2The RV data of EQ PscrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Datedtime.epochdoubleRVRadial velocity (1)km/sphys.veloc;pos.heliocentricfloate_RVError on RVkm/sstat.errorfloatS/NSignal to noise ratiostat.snrfloattexpExposure timestime.duration;obs.exposureintInst[ALFOSC MagE] Instrument used to obtain RVinstr.setupcharJ/MNRAS/489/1556/table3Results of a circular orbital fit after folding the RVs of PHL 457 to orbital phaseSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintgammaSystemic velocitykm/sphys.veloc;pos.heliocentricfloate_gammaError on gammakm/sstat.errorfloatRVRadial velocitykm/sphys.veloc;pos.heliocentricfloate_RVError on RVkm/sstat.errorfloatrmsRVrms uncertainty on RVkm/sstat.errorfloatVCRadial Velocity curvemeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/MNRAS/489/1556/table4The results of the SED fit for PHL 457, based on a Gaia distance of 577+/-21pc and extinction E(B-V)=0.023^+0.016^_-0.023_LstarLuminositysolLumphys.luminosity;em.optfloate_LstarError on LstarsolLumstat.errorfloatMstarStar mass (2)solMassphys.massfloate_MstarError on MstarsolMassstat.errorfloatchi2Reduced chi-squared of the fitstat.fit.chi2;stat.fit.param;meta.modelledfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFitType of the fit (Free or Fixed) (1)meta.notecharTeffEffective temperatureKphys.temperature.effectiveinte_TeffError on TeffKstat.error;phys.temperature.effectiveintRadRadiussolRadphys.size.radiusfloate_RadError on RadsolRadstat.errorfloatJ/MNRAS/489/1556/table5Frequency list of PHL 457 obtained with pre-whiteningS/NSignal to noise ratiostat.snrfloatn-n0? n value relative to an arbitrary zero-point n_0_stat.fit.paramintnullablel? Degree of the modestat.fit.paramintnullablem? Azimuthal order of the modestat.fit.paramintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintfIDFrequency ID (1)meta.id;meta.mainchare_freqError on frequHzstat.errordoublePeriodPeriodstime.perioddoublee_PeriodError on Periodsstat.error;time.perioddoublefreqFrequencyuHzem.freqdoubleJ/MNRAS/489/1556/table6Results of a circular orbital fit to the RVs of EQ PScSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintgammaSystem velocitykm/sphys.veloc;pos.heliocentricfloate_gammaError on gammakm/sstat.errorfloatRVRadial velocitykm/sphys.veloc;pos.heliocentricfloate_RVError on RVkm/sstat.errorfloatPeriodOrbital perioddtime.perioddoublee_PeriodError on Perioddstat.error;time.perioddoubleT0Reference epoch (BJD-2457000.0)dmeta.ref;time.epochfloate_T0Error on T0dstat.errorfloatrmsRVrms uncertainty on RVkm/sstat.errorfloatVCRadial Velocity curvemeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/MNRAS/489/1556/table7Results of the SED fit for EQ Psc based on a Gaia distance 489+/-25pc and extinction E(B-V)=0.034^+0^_-0.031_recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFitType of the fit (Free or Fixed) (1)meta.notecharTeff1Effective temperature of the hot componentKphys.temperature.effectiveinte_Teff1Error on Teff1Kstat.errorintRad1Radius of the hot componentsolRadphys.size.radiusfloate_Rad1Error on Rad1solRadstat.errorfloatLstar1Luminosity of the hot componentsolLumphys.luminosity;em.optfloate_Lstar1Error on Lstar1solLumstat.errorfloatMstar1Star mass (2)solMassphys.massfloate_Mstar1Error on Mstar1solMassstat.errorfloatTeff2Effective temperature of the cool componentKphys.temperature.effectiveinte_Teff2Error on Teff2Kstat.errorintRad2Radius of the cool componentsolRadphys.size.radiusfloate_Rad2Error on Rad2solRadstat.errorfloatLstar2Luminosity of the cool componentsolLumphys.luminosity;em.optfloate_Lstar2Error on Lstar2solLumstat.errorfloatchi2Reduced chi-squared of the fitstat.fit.chi2;stat.fit.param;meta.modelledfloatJ/MNRAS/489/1556/table8Frequency list of EQ Psc obtained with pre-whiteningrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintfreqFrequencyuHzem.freqdoublee_freq? Error on frequHzstat.errordoublenullablePeriodPeriodstime.perioddoublee_Period? Error on Periodsstat.error;time.perioddoublenullableS/NSignal to noise ratiostat.snrfloatl? Degree of the modestat.fit.paramintnullablem? Azimuthal order of the modestat.fit.paramintnullablefIDFrequency ID (1)meta.id;meta.maincharJ/MNRAS/489/1556/table9sdB stars with orbital and rotation periods estimatedSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRotRotation type (Core rotation or Surface rotation)meta.notecharNameStar namemeta.id;meta.maincharr_NameReference for Name (1)meta.ref;pos.frameintPorbOrbital perioddtime.periodfloatl_ProtLimit flag on Protmeta.code.errorcharProtRotation perioddtime.periodfloate_ProtError on Prot%stat.errorcharComp[dM WD] Companion type (M dwarf or White dwarf)src.classcharMethodFeatures used to estimate the rotation period (g modes or Spectral lines)meta.notechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main