J/ApJ/793/L4ivo://CDS.VizieR/J/ApJ/793/L4doi:10.26093/cds/vizier.17939004CDSPriyal M.Banerjee D.Karak B.B.Munoz-Jaramillo A.Ravindra B.,Choudhuri A.R.Singh J.2017-07-03T13:16:56Z2017-05-12T15:41:52ZCDS support team

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

cds-question@unistra.frthe-sunmagnetic-fieldssolar-systemThe Sun has a polar magnetic field which oscillates with the 11 yr sunspot cycle. This polar magnetic field is an important component of the dynamo process which operates in the solar convection zone and produces the sunspot cycle. We have direct systematic measurements of the Sun's polar magnetic field only from about the mid-1970s. There are, however, indirect proxies which give us information about this field at earlier times. The Ca-K spectroheliograms taken at the Kodaikanal Solar Observatory during 1904-2007 have now been digitized with 4kx4k CCD and have higher resolution (~0.86 arcsec) than the other available historical data sets. From these Ca-K spectroheliograms, we have developed a completely new proxy (polar network index, hereafter PNI) for the Sun's polar magnetic field. We calculate PNI from the digitized images using an automated algorithm and calibrate our measured PNI against the polar field as measured by the Wilcox Solar Observatory for the period 1976-1990. This calibration allows us to estimate the polar fields for the earlier period up to 1904. The dynamo calculations performed with this proxy as input data reproduce reasonably well the Sun's magnetic behavior for the past century.2014ApJ...793L...4Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/793/L4CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/169/439 : Models of solar magnetic structures (Socas-Navarro, 2007)J/A+A/539/A13 : Solar bipolar magnetic fields (Yamamoto, 2012)J/ApJ/752/126 : Modeling the magnetic field in the solar coronahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/793/L4https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/793/L4http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/793/L4https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/793/L4https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/793/L4http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/793/L4GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/793/L4/fig3cA correlation plot between the strengths of solar cycles and the PNI values at the preceding minima.Cycle[15/22] Solar cycle numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs.YYear of the solar minima (1)yrtime.epochfloatRmaxMaximum sunspot number of the cycle n+1meta.numberfloatPNIKKL Polar Network Index value at end of cycle nmeta.iddoubleJ/ApJ/793/L4/fig4PNI asymmetry of the nth cycle minimum phase is plotted against the sunspot area asymmetry of the (n+1)th cycle.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCycle[15/22] Solar cycle numbermeta.id;meta.mainintSA-NNorthern hemisphere sunspot areaphys.areadoubleSA-SSouthern hemisphere sunspot areaphys.areadoubleSAASunspot area asymmetry (1)phys.areadoubleKKL-PNI-N? KKL Polar Network Index Northspect.line.profiledoublenullableKKL-PNI-S? KKL Polar Network Index Southspect.line.profiledoublenullableKKL-A? KKL Polar Network Index asymmetry (2)spect.line.profiledoublenullableJ/ApJ/793/L4/fig3abPNI and MWO facular counts for the years 1909-1990.MWO-NMWO polar facular count Northspect.line.profiledoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs.YYear of the observationyrtime.epochintKKL-NKKL Polar Network Index Northspect.line.profiledoubleKKL-SKKL Polar Network Index Southspect.line.profiledoubleMWO-S? MWO polar facular count South (1)spect.line.profiledoublenullableSA-NNorthern hemisphere sunspot areaphys.areadoubleSA-SSouthern hemisphere sunspot areaphys.areadoubleJ/ApJ/793/L4/fig2Scatter plot of KKL PNI values with the Wilcox Solar Observatory (WSO) polar field measurements for the period of 1977-1990.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs.YYear of the observationyrtime.epochintf_Obs.Y[m] Flag on Obs.Y (1)meta.codecharKKL-PNI-NKKL Polar Network Index Northspect.line.profiledoublee_KKL-PNI-NError in KKL-PNI-Nstat.errorfloatKKL-PNI-SKKL Polar Network Index Southspect.line.profiledoublee_KKL-PNI-SError in KKL-PNI-Sstat.errorfloatWSO-PF-NWSO Polar Network Index Northspect.line.profiledoublee_WSO-PF-NError in WSO-PF-Nstat.errordoubleWSO-PF-SWSO Polar Network Index Southspect.line.profiledoublee_WSO-PF-SError in WSO-PF-Sstat.errordouble