Coude Spectra of Eta Carinae and The Strongest Lines of [Fe II] and [Ni II]

Abstract

Coudé spectra of the nucleus of η Carinae in the ranges of wavelength 3100–4250 Å and H β –6850 Å have been measured. Wavelengths and estimated intensities are listed in Table IIa and b. Garstang's transition probabilities for [Fe II] and [Ni II] have been invaluable in assigning new identifications, the agreement with observed intensities being very good. Over 100 [Fe II] lines belonging to 33 multiplets and 19 [Ni II] lines belonging to 7 multiplets are indentified. The [Fe II] intensities together with Garstang's data suggest an excitation temperature of order 8500 ± 1500 °K. An interesting new identification in the ultra-violet is [N I] 3466. The [Ne III] lines disappeared temporarily in 1965, and the He I emission was simultaneously weakened. [S II] 6717, 6730 seem to have strengthened. Displaced absorptions are prominent in the Balmer lines and for other lines especially Ti II. Such structures vary with time.