J/A+A/574/A29 Tc IV, Tc V and Tc VI oscillator strengths (Werner+, 2015)
The prospective search for highly ionized technetium in hot (pre-) white dwarfs.
Werner K., Rauch T., Kucas S., Kruk J.W.
<Astron. Astrophys. 574, A29 (2015)>
=2015A&A...574A..29W 2015A&A...574A..29W
ADC_Keywords: Atomic physics
Keywords: stars: abundances - stars: evolution - stars: AGB and post-AGB -
white dwarfs - atomic data - line: identification
Abstract:
The discovery of technetium (Tc) in the atmospheres of red giants by
Merrill (1952ApJ...116...21M 1952ApJ...116...21M) constituted convincing proof that
s-process nucleosynthesis is indeed occurring in evolved stars. In
principle, Tc should still be present in the atmospheres of hot
post-AGB stars and (pre-) white dwarfs although, due to radioactive
decay, it should be present in decreasing quantities along post-AGB
evolution. The recent discovery of a large number of trans-iron group
elements in hot white dwarfs with atomic numbers in the range
A=30-56 (Zn to Ba) raises the prospect that Tc (A=43) may also be
detected. However, this is currently not feasible because no atomic
data exist for ionization stages beyond TcII. As an initial step,
we calculated atomic energy levels and oscillator strengths of
Tc IV-VI and used these data to compute non-local thermodynamic
equilibrium (NLTE) model atmospheres to estimate at which minimum
abundance level Tc could be detected. We show that Tc lines can be
found in ultraviolet spectra of hot white dwarfs provided Tc is as
abundant as other detected trans-Fe elements. We find that radiative
levitation can keep Tc in large, easily detectable quantities in the
atmosphere. A direct identification of Tc lines is still not feasible
because wavelength positions cannot be computed with necessary
precision. Laboratory measurements are necessary to overcome this
problem. Our results suggest that such efforts are beneficial to the
astrophysical community.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 4698 Tc IV energy levels
table2.dat 77 496241 Tc IV line transitions
table3.dat 90 1932 Tc V energy levels
table4.dat 77 344498 Tc V line transitions
table5.dat 90 555 Tc VI energy levels
table6.dat 77 27107 Tc VI line transitions
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See also:
J/A+A/546/A55 : Ge V and Ge VI oscillator strengths (Rauch+, 2012)
J/A+A/564/A41 : ZnIV and ZnV oscillator strengths (Rauch+, 2014)
J/A+A/566/A10 : Ba V, Ba VI, and Ba VII oscillator strengths (Rauch+, 2014)
Byte-by-byte Description of file: table1.dat table3.dat table5.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- Index [1/4698] Level index
12- 19 F8.1 cm-1 E Level energy
21 A1 --- p [o/e] Level parity (o for odd, e for even)
23- 26 F4.1 --- J [0/12] Angular momentum quantum number J
30- 32 I3 % P1 [6/100] First percentage (1)
35- 52 A18 --- Conf1 Configuration of the first percentage
56- 58 A3 --- term1 Term of the first percentage
63- 64 I2 % P2 [1/50]? Second percentage (2)
67- 84 A18 --- Conf2 Configuration of the second percentage
88- 90 A3 --- term2 Term of the second percentage
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Note (1): First percentage is the largest component from the eigenvector
for the level
Note (2): Second percentage is the largest of the remaining components from
the same eigenvector; it is ommitted if less than 1%.
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Byte-by-byte Description of file: table2.dat table4.dat table6.dat
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Bytes Format Units Label Explanations
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1- 10 F10.2 0.1nm lambda [150/500000] Wavelength λ (Å)
16- 21 I6 cm-1 E0 Lower level energy
23 A1 --- p0 [o/e] Lower level parity
26- 28 F3.1 --- J0 [0/12] Lower level quantum number J
31- 34 I4 --- i0 [1/4698] Lower level index
40- 45 I6 cm-1 E1 Upper level energy
47 A1 --- p1 [o/e] Upper level parity
49- 52 F4.1 --- J1 [0/12] Upper level quantum number J
55- 58 I4 --- i1 [1/4698] Upper level index
62- 66 F5.2 [-] loggf Calculated HFR oscillator strength value (1)
70- 77 E8.2 s-1 gA Transition probability value (2)
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Note (1): g = statistical weight of the lower level, f = oscillator strength.
Note (2): g = statistical weight of the upper level, A = transition probability.
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Acknowledgements:
Thomas Rauch, rauch(at)astro.uni-tuebingen.de
(End) Patricia Vannier [CDS] 19-Jan-2015