J/ApJ/1008/152ivo://CDS.VizieR/J/ApJ/1008/152CDSDamineli A.Almeida L.A.Jablonski F.J.Fernandez-Lajus E.Navarete F.,Martioli E.Weigelt G.Capobiango R.2026-09-18T09:10:56Z2026-09-18T10:04:02ZCDS support team

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

cds-question@unistra.frvariable-starsphotometryvisible-astronomyThe large amount of ground-based photometric measurements of eta Carinae obtained since 1940 have remained problematic for quantitative modeling due to the blending of flux from the stellar core and the surrounding circumstellar nebula. In the era of the Hubble Space Telescope (HST), spatially resolved imaging and spectrophotometry have enabled disentanglement of these components, allowing recovery of the stellar core V-band brightness from ground-based observations. We isolate the V-band fluxes of the stellar core and nebula using 1999-2020 HST (Advanced Camera for Surveys and Space Telescope Imaging Spectrograph) observations, and use these to calibrate coeval ground-based photometry. The main finding is an orbital light curve with an amplitude of +/-0.2mag, many times higher than that modeled by ellipsoidal deformation of the primary. The observations suggest that Roche lobe overflow starts at -75 days before periastron in coincidence with the start of rising in the orbital light curve, and remains for 150 days. An expanding (and afterward dissipating) gas cloud reflecting the light from the primary would explain the observed large amplitude of the orbital light curve. A sharp periodic photometric peak occurs at ~-18 days from the periastron. It is followed by a broad minimum around the superior conjunction of the secondary (T0 + 5.2 days), which we interpret as a partial eclipse of the ejected material, in coincidence with the shallow minimum in X-rays, which also has been attributed to an eclipse.2026ApJ..1008..152Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/1008/152CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/71/983 : UV spectrum of eta Car (Viotti+ 1989)J/ApJS/157/138 : UV spectrum of eta Car (Nielsen+, 2005)J/ApJS/163/173 : UV spectrum of eta Car in 2003.5 (Gull+, 2006)J/ApJS/168/289 : NUV spectrum of eta Car in 2003.5 (Nielsen+, 2007)J/other/NewA/15.108 : UBVRIH{alpha} of eta Car in 2009 (Fernandez-Lajus+ 2010)J/A+A/304/415 : eta Car uvby-Hbeta photometry 1992-94 (van Genderen+, 1995)J/A+A/343/847 : Geneva Photometry of eta Car (van Genderen+ 1999)J/AJ/129/2018 : RXTE scaled fluxes of eta Car (Corcoran+, 2005)J/A+A/493/1093 : BVRI light curves of eta Car (Fernandez-Lajus+, 2009)J/ApJS/181/473 : Analysis of the spectrum of eta Car (Nielsen+, 2009)J/A+A/540/A133 : eta Car emission spectrum (1700-10400{AA}) (Zethson+, 2012)J/A+A/594/A106 : eta Car velocity-resolved imaging (Weigelt+, 2016)J/AJ/150/109 : Spectroscopy of eta Car in 2009 (Richardson+, 2015)J/ApJ/914/47 : ISS/NICER X-ray observations of eta Car (Kashi+, 2021)J/MNRAS/505/963 : Vanishing natural coronagraph of eta Car (Damineli+, 2021)J/ApJ/933/136 : eta Cat 0.4-10keV X-ray monitoring (Espinoza-Galeas+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/1008/152https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/1008/152http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/1008/152https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/1008/152https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/1008/152http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/1008/152GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/1008/152/table1V-band photometry taken at Pico dos Dias Observatory in Aug/2025recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Datedtime.epochdoubleVmagV-band magnitude (1)magphot.mag;em.opt.Vfloate_VmagUncertainty on V-band magnitudemagstat.error;phot.magfloatJ/ApJ/1008/152/table2BVRI-band photometry taken at La Plata in Jan-Jun 2017recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Datedtime.epochdoubleBmag? B-band magnitude (1)magphot.mag;em.opt.Bfloatnullablee_Bmag? Uncertainty on B-band magnitudemagstat.error;phot.magfloatnullableVmagV-band magnitude (1)magphot.mag;em.opt.Vfloate_VmagUncertainty on V-band magnitudemagstat.error;phot.magfloatRmag? R-band magnitude (1)magphot.mag;em.opt.Rfloatnullablee_Rmag? Uncertainty on R-band magnitudemagstat.error;phot.magfloatnullableImag? I-band magnitude (1)magphot.mag;em.opt.Ifloatnullablee_Imag? Uncertainty on I-band magnitudemagstat.error;phot.magfloatnullableJ/ApJ/1008/152/table3UBVRI-band photometry taken at Casleo 2019-2025recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Datedtime.epochdoubleUmag? U-band magnitude (1)magphot.mag;em.opt.Ufloatnullablee_Umag? Uncertainty on U-band magnitudemagstat.error;phot.magfloatnullableBmag? B-band magnitude (1)magphot.mag;em.opt.Bfloatnullablee_Bmag? Uncertainty on B-band magnitudemagstat.error;phot.magfloatnullableVmag? V-band magnitude (1)magphot.mag;em.opt.Vfloatnullablee_Vmag? Uncertainty on V-band magnitudemagstat.error;phot.magfloatnullableRmag? R-band magnitude (1)magphot.mag;em.opt.Rfloatnullablee_Rmag? Uncertainty on R-band magnitudemagstat.error;phot.magfloatnullableImag? I-band magnitude (1)magphot.mag;em.opt.Ifloatnullablee_Imag? Uncertainty on I-band magnitudemagstat.error;phot.magfloatnullable