J/ApJS/228/10 Transition probabilities for 183 lines of Cr II (Lawler+, 2017)
Improved Cr II log(gf) values and abundance determinations in the photospheres
of the Sun and metal-poor star HD 84937.
Lawler J.E., Sneden C., Nave G., Den Hartog E.A., Emrahoglu N., Cowan J.J.
<Astrophys. J. Suppl. Ser., 228, 10-10 (2017)>
=2017ApJS..228...10L 2017ApJS..228...10L (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: atomic data; stars: abundances;
stars: individual: HD 84937; stars: Population II; Sun: abundances
Abstract:
New emission branching fraction (BF) measurements for 183 lines of the
second spectrum of chromium (Cr II) and new radiative lifetime
measurements from laser-induced fluorescence for 8 levels of Cr+ are
reported. The goals of this study are to improve transition
probability measurements in Cr II and reconcile solar and stellar Cr
abundance values based on Cr I and Cr II lines. Eighteen spectra from
three Fourier Transform Spectrometers supplemented with ultraviolet
spectra from a high-resolution echelle spectrometer are used in the BF
measurements. Radiative lifetimes from this study and earlier
publications are used to convert the BFs into absolute transition
probabilities. These new laboratory data are applied to determine the
Cr abundance logε in the Sun and metal-poor star HD 84937. The
mean result in the Sun is <logε(CrII)≥5.624±0.009 compared
to <logε(CrI)≥5.644±0.006 on a scale with the hydrogen
abundance logε(H)=12 and with the uncertainty representing
only line-to-line scatter. A Saha (ionization balance) test on the
photosphere of HD 84937 is also performed, yielding
<logε(CrII)≥3.417±0.006 and <logε(CrI, lower level
excitation potential E.P.>0eV)≥3.374±0.011 for this dwarf star. We
find a correlation of Cr with the iron-peak element Ti, suggesting an
associated nucleosynthetic production. Four iron-peak elements (Cr
along with Ti, V, and Sc) appear to have a similar (or correlated)
production history-other iron-peak elements appear not to be
associated with Cr.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 58 183 Experimental atomic transition probabilities for
183 lines of Cr II organized by increasing
wavelength in air
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See also:
J/ApJ/817/53 : Fe-group elemental analysis in HD84937 (Sneden+, 2016)
J/ApJS/220/13 : Co I transition probabilities (Lawler+, 2015)
J/ApJS/215/20 : Vanadium log(gf) and transition probabilities (Lawler+, 2014)
J/ApJS/214/18 : VII log(gf) values, and V abundance in HD 84937 (Wood+ 2014)
J/ApJS/213/28 : Spectrum analysis of CrII (Sansonetti+, 2014)
J/ApJS/211/20 : NiI transition probability measurements (Wood+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)
J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)
J/A+A/554/A96 : Spectra of LiI(670.8nm) line in metal-poor stars (Lind+, 2013)
J/A+A/511/A68 : Transitions of CrII (Gurell+, 2010)
J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)
J/ApJ/667/1267 : CrI transition probabilities (Sobeck+, 2007)
J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 nm lamAir [253.4/642.2] Wavelength in air (1)
11- 19 F9.3 cm-1 UpLev [46823.3/54784.5] Upper level Value (2)
21- 23 F3.1 --- UpJ [0.5/5.5] Upper level J value (2)
25- 33 F9.3 cm-1 LowLev [11961.7/38269.6] Lower level Value (2)
35- 37 F3.1 --- LowJ [0.5/5.5] Lower level J value (2)
39- 45 F7.3 10+6/s A [0.05/250] Transition probability
47- 52 F6.3 10+6/s e_A [0.01/11] Total uncertainty in A
54- 58 F5.2 --- log(gf) [-3/0.6] Log of degeneracy times oscillator
strength
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Note (1): Computed from energy levels using the standard index of air
from Peck & Reeder (1972JOSA...62..958P 1972JOSA...62..958P).
Note (2): From Sansonetti and Nave (2014, J/ApJS/213/28).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Mar-2017