Ref: ASTROimport-36

A pulsating star inside η 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. ; Jonch-Sorensen, 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.

published in Astronomy and Astrophysics, 304, pp. 415 (1995)

Abstract: We present and analyze two seasons of intense photometric monitoring in the Stroemgren uvbyHß 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 a Cyg variables. The quasi-period is 58.56d. The linear ephemeris is: JD_max_ = 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 Hß 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.

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Royal Observatory of Belgium > Astronomy & Astrophysics
Science Articles > Peer Reviewed Articles

 Record created 2016-07-01, last modified 2016-07-01