J/AJ/135/1249ivo://CDS.VizieR/J/AJ/135/1249doi:10.26093/cds/vizier.51351249CDSHumphreys R.M.Davidson K.Koppelman M.2021-07-27T13:49:18Z2010-07-31T13:50:47ZCDS support team

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

cds-question@unistra.frbe-starsspectroscopyThe observed behavior of {eta} Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high excitation HeI{lambda}4471 and [FeIII]4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. (2001MNRAS.322..741F) noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola (1953ApJ...118..234G)'s first observations of the high-excitation features. Evidently the supply of helium-ionizing photons ({lambda}<504{AA}) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star, because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the qualitative near-constancy of the spectrum from 1900 to 1940, and {eta} Car's photometric and spectroscopic transition between 1940 and 1953.2008AJ....135.1249Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/135/1249CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/181/473 : Analysis of the spectrum of eta Car (Nielsen+, 2009)J/AJ/135/1249 : The early spectra of eta Carinae (Humphreys+, 2008)J/A+A/419/215 : Emission lines of eta Car (Hartman+, 2004)J/A+AS/133/299 : Long-term spectroscopy of eta Carinae (Damineli+ 1998)http://archive.stsci.edu/prepds/etacar/ : HST treasury program on eta Carhttp://etacar.umn.edu/ : eta car research group sitehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/135/1249https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/135/1249http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/135/1249https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/135/1249https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/135/1249http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/135/1249GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapAssociated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/AJ/135/1249defaultJ/AJ/135/1249/tablea1The Harvard objective prism plates of Eta CarrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlatePlate number (A,B, or X + NNNNN)meta.id;instr.platecharDateCalendar date of observationtime.epoch;obsnullableJDJulian date of observationJDtime.epochinttexp? Exposure timemintime.duration;obs.exposureintnullablePhasePhase in the 5.5yr spectroscopic cycletime.phasefloatComm? Comments about the spectrummeta.notecharn_CommNote on spectral features (1)meta.notecharOrigSpOriginal scan of digitized spectrummeta.id;meta.filecharRectSpExample of the rectified spectrum of the scanmeta.id;meta.filecharTracingsExtracted 1D tracings with wavelength calibration for the spectrummeta.id;meta.filechar