A spectroscopic event of eta Car viewed from different directions: The data and first results

Abstract

We present spectroscopic observations with high spectral resolution of eta Car as seen by the SE lobe of the Homunculus nebula over the 2003.5 "spectroscopic event". The observed spectra represent the stellar spectrum emitted near the pole of the star and are much less contaminated with nebular emission lines than direct observations of the central object. The "event" is qualitatively similar near the pole to what is observed in direct spectra of the star (more equator-on at 45 degree), but shows interesting differences. The observations show that the equivalent width changes of H alpha emission and other lines are less pronounced at the pole than in the line of sight. Also the absorption components appear less variable. A pronounced high-velocity absorption is present near the event in the He I lines indicating a mass-ejection event. This feature is also seen, but less pronounced, in the hydrogen lines. HeII4686 emission is observed for a brief period of time near the event and appears, if corrected for light travel time, to precede similar emission in the direct view. Our observations indicate that the event is probably not only a change in ionization and excitation structure or a simple eclipse-like event.

arXiv comment10 pages, 16 figures, accepted by A&A

References in corpus (8)

• Latitude-dependent effects in the stellar wind of Eta Carinae
• Eta Carinae: Binarity Confirmed
• Dissecting the Homunculus nebula around Eta Carinae with spatially resolved near-infrared spectroscopy
• Direct measurement of the size and shape of the present-day stellar wind of Eta Carinae
• The 2003 Shell Event in eta Carinae
• Detection of He II 4686 in eta Carinae
• The Systemic Velocity of Eta Carinae
• Eta Carinae's Brightness Variations Since 1998: HST Observations of the Central Star

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