New laboratory lifetime measurements of U II for the uranium cosmochronometer
(2001) In Astronomy & Astrophysics 372(3). p.50-52- Abstract
- We present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f<SUP>3</SUP>6d7p<SUP>6</SUP>M<SUB>13/2</SUB> at 26191 cm<SUP>-1</SUP>,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside the solar system. The lambda 3859 line canbe used as the presently most accurate cosmochronometer (Cayrel et al.cite{Cayrel}). Our value of the lifetime of the<SUP>6</SUP>M<SUB>13/2</SUB> level is 18.6+/-0.7 ns, and it confirms thef-value used in the Nature article by Cayrel et... (More)
- We present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f<SUP>3</SUP>6d7p<SUP>6</SUP>M<SUB>13/2</SUB> at 26191 cm<SUP>-1</SUP>,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside the solar system. The lambda 3859 line canbe used as the presently most accurate cosmochronometer (Cayrel et al.cite{Cayrel}). Our value of the lifetime of the<SUP>6</SUP>M<SUB>13/2</SUB> level is 18.6+/-0.7 ns, and it confirms thef-value used in the Nature article by Cayrel et al. (cite{Cayrel}),which is based on an experimental lifetime of 20+/-5 ns (Chen &Borzileri cite{Chen}). The new measurement also removes the doubt aboutthe choice between that value and other f-values in the literature,differing by a factor of 3. Adopting the same branching fraction as Chen& Borzileri (cite{Chen}) for the 3859.6 Å line, we derive agf-value of 0.68, which is 8% higher than the value used by Cayrel etal. (cite{Cayrel}). Of significance for the chronometer is also thereduced uncertainty of the radiative lifetime, 4% compared to 25%, andconsequently of the f-value, which should decrease the uncertainty inthe determination of the stellar age considerably. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/130188
- author
- Lundberg, Hans LU ; Johansson, Sveneric LU ; Nilsson, Hampus LU and Zhang, Z
- organization
- publishing date
- 2001
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- STARS: EVOLUTION, ATOMIC DATA, GALAXY: EVOLUTION
- in
- Astronomy & Astrophysics
- volume
- 372
- issue
- 3
- pages
- 50 - 52
- publisher
- EDP Sciences
- external identifiers
-
- scopus:0035373198
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361:20010608
- language
- English
- LU publication?
- yes
- id
- 6e0bbaf6-d062-4b7f-85a4-04361db4e372 (old id 130188)
- date added to LUP
- 2016-04-01 15:53:08
- date last changed
- 2024-01-10 21:31:18
@article{6e0bbaf6-d062-4b7f-85a4-04361db4e372, abstract = {{We present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f<SUP>3</SUP>6d7p<SUP>6</SUP>M<SUB>13/2</SUB> at 26191 cm<SUP>-1</SUP>,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside the solar system. The lambda 3859 line canbe used as the presently most accurate cosmochronometer (Cayrel et al.cite{Cayrel}). Our value of the lifetime of the<SUP>6</SUP>M<SUB>13/2</SUB> level is 18.6+/-0.7 ns, and it confirms thef-value used in the Nature article by Cayrel et al. (cite{Cayrel}),which is based on an experimental lifetime of 20+/-5 ns (Chen &Borzileri cite{Chen}). The new measurement also removes the doubt aboutthe choice between that value and other f-values in the literature,differing by a factor of 3. Adopting the same branching fraction as Chen& Borzileri (cite{Chen}) for the 3859.6 Å line, we derive agf-value of 0.68, which is 8% higher than the value used by Cayrel etal. (cite{Cayrel}). Of significance for the chronometer is also thereduced uncertainty of the radiative lifetime, 4% compared to 25%, andconsequently of the f-value, which should decrease the uncertainty inthe determination of the stellar age considerably.}}, author = {{Lundberg, Hans and Johansson, Sveneric and Nilsson, Hampus and Zhang, Z}}, issn = {{0004-6361}}, keywords = {{STARS: EVOLUTION; ATOMIC DATA; GALAXY: EVOLUTION}}, language = {{eng}}, number = {{3}}, pages = {{50--52}}, publisher = {{EDP Sciences}}, series = {{Astronomy & Astrophysics}}, title = {{New laboratory lifetime measurements of U II for the uranium cosmochronometer}}, url = {{https://lup.lub.lu.se/search/files/4502610/624127.pdf}}, doi = {{10.1051/0004-6361:20010608}}, volume = {{372}}, year = {{2001}}, }