SIMBAD references

We analyze the ultraviolet observations of the circumstellar nebula of η Car (the Homunculus) obtained in December 1980 with IUE. A high resolution spectrum was obtained with the IUE large aperture from 6" to 17" NW of η Car, near the H condensation (the head). The measured flux appears two orders of magnitude larger than that expected from the instrumentally scattered light (stray light). The high resolution 2295 to 3200A spectrum of the nebula is given in the form of Atlas to provide a quantitative ground for a detailed comparison with the UV spectrum of the stellar core discussed by Viotti et al. (1989). The terminal velocities of the P Cygni absorption components are similar in the stellar core and in the nebula, but the blue side of the emission appears less absorbed in the latter. The high excitation Fe II emission lines, such as the 2507-08A blend, appear sharp and very prominent in emission. A terminal velocity of ≥1000km/s is derived from the analysis of the stellar and nebular Mg II doublet. We have also identified Fe I emission lines at 2823 and 2844A which are fluorescence excited by the Mg II k line. The low resolution IUE spectrum of the condensations H (8" NW of η Car), D (5" E) and S (11" SW), is also analyzed, and the spatial physical structure of the nebula near D and S is discussed. The long-wave spectrum is dominated by broad emission blends of Fe II and Mg II. The short-wave spectrum of the X-ray emitting S condensation displays a high temperature spectrum with strong emissions of He II, N III], N IV], N V, Si III], Si IV, Fe III, and of the fluorescence Fe II 1785-88A lines. C II 1335A is also weakly present, while C III] 1907A and C IV 1550A are absent. An interstellar extinction of E_B–V≃0.4 is derived from the 2200A i.s. band in the nebular spectra.