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Resonance-enhanced two-photon ionization (RETPI) of Sih II and an anomalous, variable intensity of the lambda-1892 Si III] line in the Weigelt blobs of eta Carinae

Johansson, Sveneric LU ; Hartman, Henrik LU orcid and Letokhov, Vladilen LU (2006) In Astronomy & Astrophysics 452(1). p.253-256
Abstract
Context. The Si III] 1892 angstrom 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] lambda 1892 line. Methods. The possible intensity enhancement of the lambda 1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II. Results. The RETPI mechanism is effective on Si II in the radiation-richWeigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Ly alpha and Ly... (More)
Context. The Si III] 1892 angstrom 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] lambda 1892 line. Methods. The possible intensity enhancement of the lambda 1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II. Results. The RETPI mechanism is effective on Si II in the radiation-richWeigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Ly alpha and Ly gamma. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
HII regions, atomic processes, radiation mechanisms : non-thermal, stars : individual : eta Carinae
in
Astronomy & Astrophysics
volume
452
issue
1
pages
253 - 256
publisher
EDP Sciences
external identifiers
  • wos:000237654100027
  • scopus:33744963087
ISSN
0004-6361
DOI
10.1051/0004-6361:20054375
language
English
LU publication?
yes
id
ef26eee8-0b46-4783-9a67-a56455bc5f24 (old id 409798)
date added to LUP
2016-04-01 15:33:11
date last changed
2024-01-10 16:39:06
@article{ef26eee8-0b46-4783-9a67-a56455bc5f24,
  abstract     = {{Context. The Si III] 1892 angstrom 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] lambda 1892 line. Methods. The possible intensity enhancement of the lambda 1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II. Results. The RETPI mechanism is effective on Si II in the radiation-richWeigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Ly alpha and Ly gamma.}},
  author       = {{Johansson, Sveneric and Hartman, Henrik and Letokhov, Vladilen}},
  issn         = {{0004-6361}},
  keywords     = {{HII regions; atomic processes; radiation mechanisms : non-thermal; stars : individual : eta Carinae}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{253--256}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy & Astrophysics}},
  title        = {{Resonance-enhanced two-photon ionization (RETPI) of Sih II and an anomalous, variable intensity of the lambda-1892 Si III] line in the Weigelt blobs of eta Carinae}},
  url          = {{http://dx.doi.org/10.1051/0004-6361:20054375}},
  doi          = {{10.1051/0004-6361:20054375}},
  volume       = {{452}},
  year         = {{2006}},
}