A model for the origin of the anomalous and very bright UV lines of Fe II in gaseous condensations of the star eta Carinae
(2001) In Astronomy & Astrophysics 378. p.266-278- Abstract
- We present a qualitative physical model of the origin of two very brightUV lines of Fe II at 2507-2509 Å, present in high-resolutionspectra of gaseous condensations (blobs) close to the central star ofeta Carinae. The spectra have been obtained with the Hubble SpaceTelescope (HST). The model is based on a type of Bowen mechanism withselective photoexcitation of Fe II by a broad HLyalpha profile,generated in the HII region and diffusely transferred to the opticallythick HI region. The frequency distribution by large Doppler diffusioninto the HI region provides a substantial broadening of HLyalpha , whichmakes it possible to selectively photo-excite short-lived (~1 ns) statesat 11.2 eV in Fe II. Within the frame of the present model the... (More)
- We present a qualitative physical model of the origin of two very brightUV lines of Fe II at 2507-2509 Å, present in high-resolutionspectra of gaseous condensations (blobs) close to the central star ofeta Carinae. The spectra have been obtained with the Hubble SpaceTelescope (HST). The model is based on a type of Bowen mechanism withselective photoexcitation of Fe II by a broad HLyalpha profile,generated in the HII region and diffusely transferred to the opticallythick HI region. The frequency distribution by large Doppler diffusioninto the HI region provides a substantial broadening of HLyalpha , whichmakes it possible to selectively photo-excite short-lived (~1 ns) statesat 11.2 eV in Fe II. Within the frame of the present model the intenseHLyalpha radiation induces a depletion of the lower, long-lived (~1 ms)level of the strong UV lines by photoionization. The subsequentrecombination of Fe III explains the appearance of the ``forest'' ofnarrow Fe II lines. The possibility of a cyclic process is alsodiscussed, where HLyalpha induces depletion to bound states, which havefast decays in the far-UV to the lower state of the Bowen pumpingchannel. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/130136
- author
- Johansson, Sveneric LU and Letokhov, Vladilen LU
- organization
- publishing date
- 2001
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- RADIATION MECHANSIMS: NON-THERMAL, ATOMIC PROCESSES, LINE: FORMATION, STARS: INDIVIDUAL: ETA CARINAE
- in
- Astronomy & Astrophysics
- volume
- 378
- pages
- 266 - 278
- publisher
- EDP Sciences
- external identifiers
-
- scopus:0035471524
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361:20011062
- language
- English
- LU publication?
- yes
- id
- 4b42f2b4-e541-4177-9352-3e77b52c9b3b (old id 130136)
- date added to LUP
- 2016-04-01 17:14:48
- date last changed
- 2024-02-27 14:28:46
@article{4b42f2b4-e541-4177-9352-3e77b52c9b3b, abstract = {{We present a qualitative physical model of the origin of two very brightUV lines of Fe II at 2507-2509 Å, present in high-resolutionspectra of gaseous condensations (blobs) close to the central star ofeta Carinae. The spectra have been obtained with the Hubble SpaceTelescope (HST). The model is based on a type of Bowen mechanism withselective photoexcitation of Fe II by a broad HLyalpha profile,generated in the HII region and diffusely transferred to the opticallythick HI region. The frequency distribution by large Doppler diffusioninto the HI region provides a substantial broadening of HLyalpha , whichmakes it possible to selectively photo-excite short-lived (~1 ns) statesat 11.2 eV in Fe II. Within the frame of the present model the intenseHLyalpha radiation induces a depletion of the lower, long-lived (~1 ms)level of the strong UV lines by photoionization. The subsequentrecombination of Fe III explains the appearance of the ``forest'' ofnarrow Fe II lines. The possibility of a cyclic process is alsodiscussed, where HLyalpha induces depletion to bound states, which havefast decays in the far-UV to the lower state of the Bowen pumpingchannel.}}, author = {{Johansson, Sveneric and Letokhov, Vladilen}}, issn = {{0004-6361}}, keywords = {{RADIATION MECHANSIMS: NON-THERMAL; ATOMIC PROCESSES; LINE: FORMATION; STARS: INDIVIDUAL: ETA CARINAE}}, language = {{eng}}, pages = {{266--278}}, publisher = {{EDP Sciences}}, series = {{Astronomy & Astrophysics}}, title = {{A model for the origin of the anomalous and very bright UV lines of Fe II in gaseous condensations of the star eta Carinae}}, url = {{https://lup.lub.lu.se/search/files/4919012/624120.pdf}}, doi = {{10.1051/0004-6361:20011062}}, volume = {{378}}, year = {{2001}}, }