Resonance - Enhanced Two - Photon Ionization ( RETPI ) of Si and an Anomalous , Variable Intensity of the λ 1892 Si ] Line in the Weigelt Blobs of Eta Carinae
نویسندگان
چکیده
The Si III] 1892 Å intercombination line shows an anomalously high intensity in spectra of the radiation-rich Weigelt blobs in the vicinity of Eta Carinae. The line disappears during the 100 days long spectral events occurring every 5.5 years. The aim is to investigate whether resonance-enhanced two-photon ionization (RETPI) is a plausible excitation mechanism for the Si III] λ1892 line. The possible intensity enhancement of the λ1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II. The RETPI mechanism is effective on Si in the radiation-rich Weigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Lyα and Lyγ.
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