J/ApJ/1008/152 eta Car historical light curves (Damineli+, 2026)
eta Carinae's Historical Light Curve:
Evidence for Cyclic Roche Lobe Overflow from the Primary Star.
Damineli A., Almeida L.A., Jablonski F.J., Fernandez-Lajus E., Navarete F.,
Martioli E., Weigelt G., Capobiango R.
<Astrophys. J. 1008, 152 (2026)>
=2026ApJ..1008..152D 2026ApJ..1008..152D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Photometry ; Optical
Keywords: Massive stars
Abstract:
The 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.
Description:
Optical photometry obtained at different telescopes are provided
Objects:
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RA (2000) DE Designation(s)
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10 45 03.54 -59 41 03.9 eta Car = HD 93308
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 23 13 V-band photometry taken at Pico dos Dias
Observatory in Aug/2025
table2.dat 60 11 BVRI-band photometry taken at La Plata
in Jan-Jun 2017
table3.dat 72 310 UBVRI-band photometry taken at Casleo 2019-2025
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See also:
J/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 : UBVRIHα 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 (1700-10400Å) (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)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.3 d JD Julian Date
13- 17 F5.3 mag Vmag V-band magnitude (1)
19- 23 F5.3 mag e_Vmag Uncertainty on V-band magnitude
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Note (1): Telescope: 0.05-m (S50 ZWO).
Magnitudes are in the La Plata photometric system.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d JD Julian Date
14- 18 F5.3 mag Bmag ?=- B-band magnitude (1)
20- 24 F5.3 mag e_Bmag ?=- Uncertainty on B-band magnitude
26- 30 F5.3 mag Vmag V-band magnitude (1)
32- 36 F5.3 mag e_Vmag Uncertainty on V-band magnitude
38- 42 F5.3 mag Rmag ?=- R-band magnitude (1)
44- 48 F5.3 mag e_Rmag ?=- Uncertainty on R-band magnitude
50- 54 F5.3 mag Imag ?=- I-band magnitude (1)
56- 60 F5.3 mag e_Imag ?=- Uncertainty on I-band magnitude
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Note (1): Telescope: 0.80-m Virpi S. Niemela (VSN).
Camera: Photometrics STAR I CCD.
Observatory: Observatorio Astronomico de La Plata, La Plata, Argentina.
Magnitudes are in the La Plata photometric system.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d JD Julian Date
14- 18 F5.3 mag Umag ?=- U-band magnitude (1)
20- 24 F5.3 mag e_Umag ?=- Uncertainty on U-band magnitude
26- 30 F5.3 mag Bmag ?=- B-band magnitude (1)
32- 36 F5.3 mag e_Bmag ?=- Uncertainty on B-band magnitude
38- 42 F5.3 mag Vmag ?=- V-band magnitude (1)
44- 48 F5.3 mag e_Vmag ?=- Uncertainty on V-band magnitude
50- 54 F5.3 mag Rmag ?=- R-band magnitude (1)
56- 60 F5.3 mag e_Rmag ?=- Uncertainty on R-band magnitude
62- 66 F5.3 mag Imag ?=- I-band magnitude (1)
68- 72 F5.3 mag e_Imag ?=- Uncertainty on I-band magnitude
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Note (1): Telescope: Jorge Sahade 2.15-m telescope.
Observatory: Complejo Astronomico El Leoncito (CASLEO), San Juan, Argentina.
Magnitudes are in the La Plata photometric system.
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Acknowledgements:
Felipe Navarete, navarete(at)gmail.com
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 17-Sep-2026