On the He II Emission In Eta Carinae and the Origin of Its Spectroscopic Events

J. C. Martin, K. Davidson, R. M. Humphreys, D. J. Hillier, K. Ishibashi, et al

AA(Univeristy Of Minnesota), AB(Univeristy Of Minnesota), AC(Univeristy Of Minnesota), AD(Univeristy Of Pittsburg), AE(MIT)

We report Hubble Space Telescope (HST) observations of emission in Eta Carinae near 4680 {\AA}, presumably He II 4687, which are not spatially resolved from the central star. The emission was not detected in the spectrum from 1998.0 to 2003.0, or after the spectroscopic event in 2003.5. It appeared in early 2003, rapidly grew to a larger brightness than the previous authors reported, and then disappeared suddenly near 2003.5. For several weeks the He II 4687 luminosity was too high to explain easily in most proposed models for Eta Car's spectroscopic events. According to our analyses, this feature appears most consistent with a wind-disturbance or mass-ejection type of model with relatively high gas densities. An unusual form of radiative excitation, making use of trapped He II 304 resonance photons, may have played a major role.

Reference: submitted to the ApJ
Status: Manuscript has been submitted

Weblink: http://arxiv.org/abs/astro-ph/0504151


Email: martin@etacar.umn.edu