The Binarity of Eta Carinae and its Similarity to Related Astrophysical Objects

Abstract

I examine some aspects of the interaction between the massive star Eta Carinae and its companion, in particular during the eclipse-like event, known as the spectroscopic event or the shell event. The spectroscopic event is thought to occur when near periastron passages the stellar companion induces much higher mass loss rate from the primary star, and/or enters into a much denser environment around the primary star. I find that enhanced mass loss rate during periastron passages, if it occurs, might explain the high eccentricity of the system. However, there is not yet a good model to explain the presumed enhanced mass loss rate during periastron passages. In the region where the winds from the two stars collide, a dense slow flow is formed, such that large dust grains may be formed. Unlike the case during the 19th century Great Eruption, the companion does not accrete mass during most of its orbital motion. However, near periastron passages short accretion episodes may occur, which may lead to pulsed ejection of two jets by the companion. The companion may ionize a non-negligible region in its surrounding, resembling the situation in symbiotic systems. I discuss the relation of some of these processes to other astrophysical objects, by that incorporating Eta Car to a large class of astrophysical bipolar nebulae.

Updated version. ApJ, in press

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Cited by in corpus (16)

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• Accretion onto the Companion of Eta Carinae During the Spectroscopic Event: II. X-Ray Emission Cycle
• An Indication for the Binarity of P Cygni from Its Seventeenth Century Eruption
• Comparing Eta Carinae with the Red Rectangle
• Accretion onto the Companion of Eta Carinae During the Spectroscopic Event: III. the He II 4686 Line
• Modelling the Radio Light Curve of Eta Carinae
• Accretion onto the Companion of Eta Carinae During the Spectroscopic Event. IV. the Disappearance of Highly Ionized Lines
• Accretion at the periastron passage of Eta Carinae
• Simulating the Response of the Secondary Star of Eta Carinae to Mass Accretion at Periastron Passage
• The Formation of Slow-Massive-Wide Jets
• Fast Ejecta Resulted from Jet-Wind Interaction in the Great Eruption of Eta Carinae
• Wind Collision and Accretion Simulations of the Massive Binary System HD 166734
• Discovery of Five Candidate Analogs for $\eta$Carinae in Nearby Galaxies
• On continuum driven winds from rotating stars