A Lifetime of Influence: Abstracts, Talks, and Posters
 

Eta Carinae: a long period binary

Augusto Damineli
IAGUSP-Brazil

There have been many suggestions, along the last century, that eta Carinae as a binary system, based on different assumptions. A new chapter on this subject started with the seminal paper: "eta Carinae: a long period binary?" by Damineli, Conti and Lopes (1997). The model, based on strict periodicity (5.54-yr) and on the orbital solution of a radial-velocity curve, resulted in a highly eccentric system in which a hotter and fainter secondary star orbits the well know LBV star. The luminous nature of the companion stars with strong winds and the close periastron passages suggested a powerful wind-wind collision. The model raised a hot debate because the line shifts were measured on broad emission line profiles. However, after 11 years of progress the basic scenario continues to be valid. More than that, the huge amount of X-rays data revealed clearly the wind-wind collision and provided constraints to the nature of the unseen hot companion. It is possible that we will never discover the exact orbital parameters, but, it is helpful to understanding the behavior of the main star, when we take in mind that it belongs to a binary system.