Eta Carinae: Binarity Confirmed

Abstract

We report the recovery of a spectroscopic event in eta Carinae in 1997/98 after a prediction by Damineli (1996). A true periodicity with P = 2020+-5 days (0.2% uncertainty) is obtained. The line intensities and the radial-velocity curve display a phase-locked behavior implying that the energy and dynamics of the event repeat from cycle to cycle. This rules out S Doradus oscillation or multiple shell ejection by an unstable star as the explanation of the spectroscopic events. A colliding-wind binary scenario is supported by our spectroscopic data and by X-ray observations. Although deviations from a simple case exist around periastron, intensive monitoring during the next event (mid 2003) will be crucial to the understanding of the system.

13 pages, accepted by ApJ Letters (January 2000)

Cited by in corpus (93)

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