Anomalous Spectral Lines in Space and Laboratory Plasmas - Studies with HST and CRYRING

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Eta Carinae is one of the most massive and luminous stars in the Galaxy. A huge bipolar nebula and an equatorial disk give the object a characteristic shape. Close to the star there are gas clouds, which emit intriguing emission line spectra. One such region, the strontium filament, is studied in more detail in this thesis, and the identities of 600 emission lines are reported. Some of these require extra treatment, viz. allowed and forbidden lines of Ti II and Sr II. Many thin astrophysical plasmas emit parity-forbidden lines, which can be used to diagnose the plasma. The upper levels of these lines are metastable states, which have radiative lifetimes of the order of 1 second compared to 1 nanosecond for ordinary states. We have performed measurements of metastable lifetimes in complex ions applying a laser probing technique on a stored ion beam at the storage ring CRYRING (MSL, Stockholm). This thesis reports on 4 lifetimes in Fe II and 2 in Ti II, the first measured in such complex systems. The lifetimes are in the range 0.23 to 28 s. Experimental absolute transition probabilities for forbidden lines in [Fe II] are derived by combining the experimental metastable lifetimes with astrophysical branching fractions (BF). The BF’s are derived from spectra of the Weigelt blobs of Eta Carinae, which contain strong forbidden [Fe II] lines. In some stars the intensity of emission lines from specific high-excitation levels is greatly enhanced. They are explained as fluoresence lines from energy levels, which have an enhanced population due to selective photoexcitation. This is caused by an accidental coincidence in wavelength between a strong emission line and the pumped transition. We report on fluorescence lines and pumped levels in Fe II observed in the symbiotic star RR Telescopii.

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Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • magnetic resonance, supraconductors, magnetic and optical properties, electrical, Condensed matter:electronic structure, strontium, titanium, CRYRING, iron, STIS, metastable levels, HST, RR Telesopii, Eta Carinae, line identification, fluorescence, forbidden lines, Atomic Spectroscopy, lifetime measurements, Astronomy, Astronomi, rymdvetenskap, cosmic chemistry, space research, spektroskopi, supraledare, magnetiska och optiska), egenskaper (elektriska, Kondenserade materiens egenskaper:elektronstruktur, magnetisk resonans, relaxation, spectroscopy, kosmisk kemi, Fysicumarkivet A:2003:Hartman
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • [unknown], [unknown], Supervisor, External person
Award date2003 Dec 19
Publisher
  • Lund Observatory, Lund University
Print ISBNs91-628-5903-X
StatePublished - 2003

Bibliographic note

Defence details Date: 2003-12-19 Time: 10:15 Place: Lundmarksalen External reviewer(s) Name: Garnir, Henri-Pierre Title: Professor Affiliation: [unknown] ---

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Related research output

Henrik Hartman, Gull, T., Johansson, S. & Smith, N. 2004 In : Astronomy & Astrophysics. 419, 1, p. 215-224

Research output: Contribution to journalArticle

Henrik Hartman, Derkatch, A., Donnelly, M. P., Gull, T., Hibbert, A., Johansson, S., Hans Lundberg, Mannervik, S., Norlin, L-O., Rostohar, D., Royen, P. & Schef, P. 2003 In : Astronomy & Astrophysics. 397, 3, p. 1143-1149

Research output: Contribution to journalArticle

Zethson, T., Gull, T. R., Henrik Hartman, Johansson, S., Davidson, K. & Ishibashi, K. 2001 In : Astronomical Journal. 122, 1, p. 322-326

Research output: Contribution to journalArticle

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