J/PASP/131/H4201ivo://CDS.VizieR/J/PASP/131/H4201doi:10.26093/cds/vizier.61323201CDSRatzloff J.K.Corbett H.T.Law N.M.Barlow B.N.Glazier A.,Howard W.S.Fors O.Del Ser D.Trifonov T.2025-09-09T14:15:01Z2019-09-12T14:42:45ZCDS support team

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

cds-question@unistra.frvariable-starseclipsing-binary-starsThe regions around the celestial poles offer the ability to find and characterize long-term variables from ground-based observatories. We used multi-year Evryscope data to search for high-amplitude (~=5% or greater) variable objects among 160000 bright stars (m_v_<14.5) near the South Celestial Pole. We developed a machine-learning-based spectral classifier to identify eclipse and transit candidates with M-dwarf or K-dwarf host stars, and potential low-mass secondary stars or gas-giant planets. The large amplitude transit signals from low-mass companions of smaller dwarf host stars lessens the photometric precision and systematics removal requirements necessary for detection, and increases the discoveries from long-term observations with modest light-curve precision among the faintest stars in the survey. The Evryscope is a robotic telescope array that observes the Southern sky continuously at 2-minute cadence, searching for stellar variability, transients, transits around exotic stars and other observationally challenging astrophysical variables. The multi-year photometric stability is better than 1% for bright stars in uncrowded regions, with a 3{sigma} limiting magnitude of g=16 in dark time. In this study, covering all stars 9<m_v_<14.5, in declinations -75{deg} to -90{deg}, and searching for high-amplitude variability, we recover 346 known variables and discover 303 new variables, including 168 eclipsing binaries. We characterize the discoveries and provide the amplitudes, periods, and variability type. A 1.7R_J_ planet candidate with a late K-dwarf primary was found and the transit signal was verified with the PROMPT telescope network. Further follow-up revealed this object to be a likely grazing eclipsing binary system with nearly identical primary and secondary K5 stars. Radial-velocity measurements from the Goodman Spectrograph on the 4.1 meter SOAR telescope of the likely lowest-mass targets reveal that six of the eclipsing binary discoveries are low-mass (0.06-0.37M_{sun}_) secondaries with K-dwarf primaries, strong candidates for precision mass-radius measurements.2019PASP..131h4201Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/PASP/131/H4201CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)J/PASP/131/G5001 : New variable stars and eclipsing binaries (Ratzloff+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/PASP/131/H4201https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/PASP/131/H4201http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/PASP/131/H4201https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/PASP/131/H4201https://vizier.iucaa.in/viz-bin/votable?-source=J/PASP/131/H4201http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/PASP/131/H4201GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/PASP/131/H4201/table10 (Variable Star discoveries)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/PASP/131/H4201/table10?https://vizier.iucaa.in/viz-bin/conesearch/J/PASP/131/H4201/table10?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/PASP/131/H4201/table10?GETtext/xml+votable180.050000true1.0462-86.36680.005555555555555556Cone search capability for table J/PASP/131/H4201/table11 (Eclipsing Binary discoveries)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/PASP/131/H4201/table11?https://vizier.iucaa.in/viz-bin/conesearch/J/PASP/131/H4201/table11?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/PASP/131/H4201/table11?GETtext/xml+votable180.050000true6.1901-78.67530.0055555555555555565/8200 9224 9228 10249 10281 6/32775 32777 32782 32785-32786 32789 32794 32804-32806 32813 32821-32822 32832-32833 32835 32837 32842-32843 32846 32849 32852-32853 32855 32859-32860 32865-32866 32868 32872-32874 32876 32884 32897 32903 32934-32935 32937 32952 32956 32963-32965 32971 33024 33028 33030 33032-33033 33284-33285 36865 36869-36870 36874-36875 36885-36886 36888 36890 36893-36895 36900 36905-36906 36908-36909 36917 36920-36921 36929-36930 36934-36935 36937 36947 36951-36952 36954 36960-36961 36965-36966 36971 36973-36974 36996 36998 37000-37001 37005-37006 37013 37018 37020 37022 37025 37027 37031 37034 37036 37065 37120 37122 37381 37384 40963 40973 40975 40977-40979 40981-40983 40985 40988 40990 40993-40994 41000-41001 41003-41005 41007-41008 41010-41012 41017 41024-41026 41028 41030-41031 41034-41035 41041-41042 41044 41049 41051 41056 41058 41065-41066 41070 41093 41100 41102-41103 41106 41110-41112 41115 41130 41132-41134 41138 41142 41155 41157-41158 41217 41221 41473-41474 45062 45065-45066 45068 45071 45077 45079 45086-45089 45091 45094 45099 45103 45119 45131 45139-45141 45143 45145-45146 45148 45155 45158 45167 45185-45186 45188 45193 45198 45200 45204-45205 45216 45228 45249 45252 45315 45568 45576-45577https://cdsarc.cds.unistra.fr/viz-bin/moc/J/PASP/131/H4201?format=asciidefaultJ/PASP/131/H4201/table10Variable Star discoveriesAmpAmplitude of the variabilitymagsrc.varfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintESIDES ID (EVRJHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharAPASS? APASS IDmeta.idintnullableRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainVmag? V magnitudemagphot.mag;em.opt.VfloatnullableRPM? Reduced proper motionphys.magAbsfloatnullableB-V? Color difference (B-V) which we use to estimate the star size and spectral type (see Section 4.2.1)magphot.color;em.opt.B;em.opt.VfloatnullableSizeStar size (ms or giant)meta.codecharSpTypeSpectral typesrc.spTypecharPerPeriodhtime.perioddoubleJ/PASP/131/H4201/table11Eclipsing Binary discoveriesRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainAPASS? APASS IDmeta.idintnullableDEJ2000Declination (J2000)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintESIDES ID (EVRJHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharVmag? V magnitudemagphot.mag;em.opt.VfloatnullableRPM? Reduced proper motionphys.magAbsfloatnullableB-V? Color difference (B-V) which we use to estimate the star size and spectral type (see Section 4.2.1)magphot.color;em.opt.B;em.opt.VfloatnullableSizeStar size (ms or giant)meta.codecharSpTypeSpectral typesrc.spTypecharPerPeriodhtime.perioddoubleAmpAmplitude of the variabilitymagsrc.varfloat