J/A+A/304/415 uvby-Hbeta photometry of Eta Car 1992-94 (van Genderen+, 1995)
A pulsating star inside Eta Carinae I. Light variations 1992-1994
van Genderen A.M., Sterken C., de Groot M., Stahl O., Andersen J.,
Andersen M.I., Caldwell J.A.R., Casey B., Clement R., Corradi W.J.B.,
Cuypers J., Debehogne H., Garcia de Maria J.M., Joench-Soerensen H.,
Vaz L.P.R., Stefl S., Suso Lopez J., Beele D., Eggenkamp I.M.M.G.,
Goecking K.-D., Jorissen A., de Koff S., Kuss C., Schoenmakers A.P.,
Vink J., Waelde E.
<Astron. Astrophys. 304, 415 (1995)>
=1995A&A...304..415V 1995A&A...304..415V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable; Stars, supergiant; Photometry, uvby, beta
Keywords: techniques: photometric -
stars: individual: η Car; variables; supergiants; oscillations
Description:
We present and analyze two seasons of intense photometric monitoring
in the Stroemgren uvbyHβ system of η Carinae (October
1992-August 1994). The luminous blue variable (LBV) in the core did
not show much S Dor activity, i.e. it was in a relatively quiescent
stage. This situation was very favourable for studying its optical
micro variations. It appears that the central LBV pulsates (presumably
in a non-radial mode) like other massive evolved stars, the α
Cyg variables. The quasi-period is 58.56d. The linear ephemeris is:
JDmax=2448875.0 +58.56 E. Support was found for the existence of the
presumed periodicity of 52.4d of the so-called "dimples", shallow dips
in the light curve which only last for a few days. The cause may be
the eclipse of a small companion or of a hot spot in an accretion
disk. The Hβ index became bluer by ∼0.07mag during the last 11/2
years and shows an oscillation in anti-phase with the 58.56d
pulsation, suggesting that the HII region(s) responsible for the
hydrogen line emission has a relatively high luminosity. This is
another reason to suppose that a second luminous source, perhaps a
luminous disk (with a hot spot), may be present in the η Car
system.
Objects concerned:
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RA (2000) DE Name(s)
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10 45 03.6 -59 41 03 eta Car = HR 4210 = 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 64 285 Stroemgren uvbyH-beta photometry of Eta Car
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See also:
J/ApJS/71/983 : UV spectrum of eta Car (Viotti+ 1989)
J/A+A/304/415 : uvby-Hbeta photometry of Eta Car 1992-94 (van Genderen+, 1995)
J/A+A/343/847 : Geneva Photometry of Eta Car (van Genderen+ 1999)
J/A+A/419/215 : Emission lines of eta Car (Hartman+, 2004)
J/AJ/129/2018 : RXTE scaled fluxes of eta Car (Corcoran+, 2005)
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/A+A/493/1093 : BVRI light curves of eta Car (Fernandez-Lajus+, 2009)
J/ApJS/181/473 : Eta Carinae: visible and near-IR analysis (Nielsen+, 2009)
J/other/NewA/15.108 : UBVRIHalpha of eta Car in 2009 (Fernandez-Lajus+ 2010)
Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 11 F11.3 d JD Julian date
12 A1 --- u_JD [:] Uncertainty flag on JD
18- 23 F6.4 mag ymag []? y Stroemgren magnitude
26- 31 F6.4 mag bmag []? b Stroemgren magnitude
33- 39 F7.4 mag vmag []? v Stroemgren magnitude
42- 47 F6.4 mag umag []? u Stroemgren magnitude
50- 55 F6.4 mag Hbmag []? Hβ Stroemgren magnitude
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(End) Simona Mei [CDS] 26-Jul-1995