Volume 452, Number 1, June II 2006
|Page(s)||253 - 256|
|Section||Interstellar and circumstellar matter|
|Published online||17 May 2006|
Resonance-enhanced two-photon ionization (RETPI) of Si II and an anomalous, variable intensity of the 1892 Si III] line in the Weigelt blobs of η Carinae
Lund Observatory, Lund University, PO Box 43, 22100, Lund, Sweden e-mail: firstname.lastname@example.org
2 Institute of Spectroscopy, Russian Academy of Sciences, 142190 Troitsk, Moscow region, Russia
Accepted: 21 February 2006
Context.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.
Aims.The aim is to investigate whether resonance-enhanced two-photon ionization (RETPI) is a plausible excitation mechanism for the Si III] λ1892 line.
Methods.The possible intensity enhancement of the λ1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II.
Results.The RETPI mechanism is effective on in the radiation-rich Weigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Lyα and Lyγ.
Key words: atomic processes / radiation mechanisms: non-thermal / HII regions / stars: individual: η Carinae
© ESO, 2006
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.