LBVs and the nature of the S Dor cycles: the case of AG Carinae

Groh, J. H.; Damineli, A.; Hillier, D. J.

LBVs and the nature of the S Dor cycles: the case of AG Carinae

Authors

Groh, J. H.

Damineli, A.

Hillier, D. J.

Description

We present the results of a detailed spectroscopic analysis of 20 years of observations of AG Carinae using the radiative transfer code CMFGEN. Among the conclusions of this work, we highlight the importance of including time-dependent effects in the analysis of the full S Dor cycle. We obtained that the mass-loss rate is approximately constant during the cool phases, implying that the S Dor-type eruptions begin well earlier than the maximum seen in the visual lightcurve. We also determined that the S Dor cycles are ultimately a consequence of an increase/decrease of the hydrostatic radius in combination with the formation of a pseudo-photosphere.
2 pages, 2 figures, to appear in the Proceedings of "Massive Stars: Fundamental Parameters and Circumstellar Interactions"