J/ApJ/773/1ivo://CDS.VizieR/J/ApJ/773/1doi:10.26093/cds/vizier.17730001CDSJetsu L.Porceddu S.Lyytinen J.Kajatkari P.Lehtinen J.,Markkanen T.Toivari-Viitala J.2017-01-23T22:00:00Z2016-10-27T13:27:19ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsThe eclipses in binary stars give precise information of orbital period changes. Goodricke J. (1783RSPT...73..474G) discovered the 2.867d period in the eclipses of Algol. The irregular orbital period changes of this longest known eclipsing binary continue to puzzle astronomers. The mass transfer between the two members of this binary should cause a long-term increase of the orbital period, but observations over two centuries have not confirmed this effect. Here, we present evidence indicating that the period of Algol was 2.850d three millennia ago. For religious reasons, the ancient Egyptians have recorded this period into the Cairo Calendar (CC), which describes the repetitive changes of the Raging one. CC may be the oldest preserved historical document of the discovery of a variable star.2013ApJ...773....1Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/773/1CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/542/A38 : LQ Hya V-band differential light curve (Lehtinen+, 2012)J/A+A/527/A136 : HD 116956 V-band differential light curve (Lehtinen+, 2011)J/MNRAS/405/1930 : Per changes of EA-, EB- and EW-types binaries (Liao+, 2010)J/A+A/383/197 : BV light curves of V511 Lyr in 1994-1996 (Lyytinen+, 2002)J/A+A/362/223 : 1984-1998 BV photometry of V815 Her (Jetsu+, 2000)J/A+A/351/212 : V1794 UBVR time series (Jetsu+, 1999)J/A+A/321/L33 : Terrestrial impact cratering rate (Jetsu 1997)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/773/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/773/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/773/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/773/1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/773/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/773/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/773/1/table1Cairo Calendar (CC) prognoses for one Egyptian yearrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintD[1/30] Day of month (1)time.epochintAIPrognoses of Aket I (Month=1) (2)stat.fit.paramcharAIIPrognoses of Aket II (Month=2) (2)stat.fit.paramcharAIIIPrognoses of Aket III (Month=3) (2)stat.fit.paramcharAIVPrognoses of Aket IV (Month=4) (2)stat.fit.paramcharPIPrognoses of Peret I (Month=5) (2)stat.fit.paramcharPIIPrognoses of Peret II (Month=6) (2)stat.fit.paramcharPIIIPrognoses of Peret III (Month=7) (2)stat.fit.paramcharPIVPrognoses of Peret IV (Month=8) (2)stat.fit.paramcharSIPrognoses of Shemu I (Month=9) (2)stat.fit.paramcharSIIPrognoses of Shemu II (Month=10) (2)stat.fit.paramcharSIIIPrognoses of Shemu III (Month=11) (2)stat.fit.paramcharSIVPrognoses of Shemu IV (Month=12) (2)stat.fit.paramcharJ/ApJ/773/1/table3Time points for all prognoses of Table 1X[GS] Prognosisstat.fit.paramcharNE[1/360] Egyptian day; NE=30(M-1)+Dtime.epochintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintD[1/30] Day numbertime.epochintM[1/12] Month numbertime.epochintti(2_62)N_0_=62 in Eq. 1 and day division of Eq. 2 (1)dtime.epochfloatti(2_187)N_0_=187 in Eq. 1 and day division of Eq. 2 (1)dtime.epochfloatti(2_307)N_0_=307 in Eq. 1 and day division of Eq. 2 (1)dtime.epochfloatti(3_62)N_0_=62 in Eq. 1 and day division of Eq. 3 (1)dtime.epochfloatti(3_187)N_0_=187 in Eq. 1 and day division of Eq. 3 (1)dtime.epochfloatti(3_307)N_0_=307 in Eq. 1 and day division of Eq. 3 (1)dtime.epochfloat