Journal Article

Prediction for the He <span class="smallCaps">i</span>λ10830 Å absorption wing in the coming event of η Carinae

Amit Kashi and Noam Soker

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 394, issue 2, pages 923-928
Published in print April 2009 | ISSN: 0035-8711
Published online March 2009 | e-ISSN: 1365-2966 | DOI:
Prediction for the He iλ10830 Å absorption wing in the coming event of η Carinae

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We propose an explanation for the puzzling appearance of a wide blue absorption wing in the He iλ10830 Å P Cygni profile of the massive binary star η Car several months before periastron passage. Our basic assumption is that the colliding winds region is responsible for the blue wing absorption. By fitting observations, we find that the maximum outflow velocity of this absorbing material is ∼2300 km s−1. We also assume that the secondary star is towards the observer at periastron passage. With a toy model, we achieve two significant results. (1) We show that the semimajor axis orientation we use can account for the appearance and evolution of the wide blue wing under our basic assumption. (2) We predict that the Doppler shift (the edge of the absorption profile) will reach a maximum 0–3 weeks before periastron passage, and not necessarily exactly at periastron passage or after periastron passage.

Keywords: binaries: general; stars: mass-loss; stars: individual: η Car; stars: winds, outflows

Journal Article.  4198 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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