stark broadening of b iv lines for astrophysical and laboratory plasma research
DESCRIPTION
بوره بورق 2 s 2 2p 1. Stark broadening of B IV lines for astrophysical and laboratory plasma research. M S Dimitrijevi ć , M Christova , Z Simi ć , A Kova će vi ć , S Sahal-Bréchot Astronomical Observatory , Volgina 7, 11060 Belgrade 38, Serbia - PowerPoint PPT PresentationTRANSCRIPT
Stark broadening of B IV lines for astrophysical and laboratory
plasma researchM S Dimitrijević, M Christova, Z Simić, A Kovaćević, S Sahal-Bréchot
Astronomical Observatory, Volgina 7, 11060 Belgrade 38, SerbiaDepartment of Applied Physics, Technical University-Sofia, 1000 Sofia, Bulgaria
Observatoire de Paris, 92195 Meudon Cedex, France
بوره بورق2s22p1
SCSLSA Banja Koviljača 13.05.2013
Stark broadening in Astrophysics
Efficient for modelling and analysing spectra of moderately hot (А), hot (В), and very hot (О) stars.
Dominant collisional line broadening process in all layers of the atmosphere of white dwarfs.
Well applied for accurate spectroscopic diagnostics and modelling.
Astrophysical plasma research
SCSLSA Banja Koviljača 13.05.2013
SCSLSA Banja Koviljača 13.05.2013
White dwarf stars in the Milky Way Galaxy
Faint white dwarf star in globular cluster ngc 6397
Astrophysical plasma research
Interpretation of the spectra of white dwarfs allows understanding the evolution of these very old stars
Cosmochronometry - studying stellar evolution to determine the age and history of stellar populations.
SCSLSA Banja Koviljača 13.05.2013
Astrophysical plasma research
Evolution of the Universe, birth, growing and death of the stars – major interest.
The light element trio LiBeB – at the centre of the astrophysical puzzles.
The origins of LiBeB to big bang nucleosynthesis, cosmic-ray spallation, and stellar evolution.
Abundance determination of LiBeB – provide data on the astrophysical processes that can produce and destroy these rare elements.
The light elements – sensitive probes of stellar models the stable isotopes of all three consist of nuclei with small binding energies that are destroyed easily by (p, a) reactions at modest temperatures.
SCSLSA Banja Koviljača 13.05.2013
Cosmology
Special interest – the origin and evolution of boron: hardly produced by standard big bang nucleosynthesis and cannot be produced by nuclear fusions in stellar interiors.
Disagreements between traditional models for these processes and observations:
The theory predicts that Be and B abundance would scale quadratically with the overall metal abundance, however they scale linearly.
Model: 11B / 10B ≈ 2,5
Observations: 11B / 10B ≈ 4 The surface abundance of a light elements is less than the
star’s initial abundance – an observational constraint for testing models of stellar interiors.
SCSLSA Banja Koviljača 13.05.2013
? boron
Boron alone is observable in hot stars.
The studies confirm the conclusion that boron is mainly produced by primary process in the early Galaxy.
A principle goal of most of studies of hot stars – to establish the present-day boron abundance in order to improve the understanding of the Galactic chemical evolution of boron.
Boron in hot stars – a tracer of some of the various processes affecting a star’s surface composition that are not included in the standard models of stellar evolution.
Boron abundance – the clue to unravelling the nonstandard processes that affect young hot stars.
SCSLSA Banja Koviljača 13.05.2013
Boron and hot stars
Spectral line profile
Knowledge of numerous profiles, especially for trace elements, which are used as useful probes for modern spectroscopic diagnostics.
SCSLSA Banja Koviljača 13.05.2013
STARK broadening theory
elffff
iiiie vvdvvvfnW
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''
02
dR
Rpddvvvfd
3
2sin20
SCSLSA Banja Koviljača 13.05.2013
Sahal-Bréchot theory based on the semi-classical perturbation formalism
Calculation of Stark parameters using: - atomic data from TOPbase catalogue- calculated oscillator strengths using Bates & Damgaard method and experimental values of energy levels from the reference of Kramida at all.
Results
Electron impact widths of B IV spectral line versus the temperature for electron density 1018 cm-3.
SCSLSA Banja Koviljača 13.05.2013
0 1x105 2x105 3x105 4x105 5x105
5,0x10-5
1,0x10-4
1,5x10-4
2,0x10-4
1s2 1S – 1s2p 1P°n
e = 1.1018 cm-3
Ele
ctro
n im
pact
wid
th (A
)
Temperature (K)
Width: 91 – 30 % - electron contribution 3 – 20 % - proton contribution5 – 50 % ionized helium contribution
SCSLSA Banja Koviljača 13.05.2013
0 1x105 2x105 3x105 4x105 5x105
-3,0x10-5
-2,0x10-5
-1,0x10-5
0,0
1s2 1S – 1s2p 1P°n
e = 1.1018 cm-3
Ele
ctro
n im
pact
shi
ft (A
)
Temperature (K)
Electron impact shifts of B IV spectral line versus the temperature for electron density 1018 cm-3.
Results
Shift: 60 - 70 % ionized helium 24 – 28 % - proton contribution5 – 14 % - electron contribution
SCSLSA Banja Koviljača 13.05.2013
1014 1015 1016 1017 1018 1019 1020 1021
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Ele
ctro
n im
pact
wid
th (A
)
Electron density (cm-3)
1s2 1S - 1s3p 1Po
T = 200 000 K
Results
Electron impact widths of B IV spectral line versus electron density for temperature 2E5 K.
Spectral series
SCSLSA Banja Koviljača 13.05.2013
Electron impact width of spectral lines within one spectral series versus the principle quantum number for temperature 1e5 K and electron density 1014 cm-3.
SCSLSA Banja Koviljača 13.05.2013
2 3 4 5 6 7
0,0
2,0x109
4,0x109
6,0x109
8,0x109
1,0x1010
1s2 1S – 1snp 1P°T = 100 000 Kn
e = 1.1014 cm-3
Ele
ctro
n im
pact
wid
th (s
-1)
Principal quantum number
Results
SCSLSA Banja Koviljača 13.05.2013
0 1x105 2x105 3x105 4x105 5x105
5,0x1010
1,0x1011
1,5x1011 1s2s 1S – 1snp 1P°n
e = 1.1017 cm-3
Ele
ctro
n im
pact
wid
th (s
-1)
Temperature (K)
Electron impact widths of B IV spectral line versus the temperature for electron density 1018 cm-3.
Results
SCSLSA Banja Koviljača 13.05.2013
0 1x105 2x105 3x105 4x105 5x105-9,0x109
-8,5x109
-8,0x109
-7,5x109
-7,0x109
-6,5x109
-6,0x109
1s2s 1S – 1snp 1P°n
e = 1.1017 cm-3
Ele
ctro
n im
pact
shi
ft (s
-1)
Temperature (K)
Results
Electron impact shifts of B IV spectral line versus the temperature for electron density 1017 cm-3.
0 1x105 2x105 3x105 4x105 5x105
-3,0x10-5
-2,0x10-5
-1,0x10-5
0,0
1s2 1S – 1s2p 1P°n
e = 1.1018 cm-3
Ele
ctro
n im
pact
shi
ft (A
)
Temperature (K)
Calculation of Stark parameters using:
- atomic data from TOPbase catalogue
- calculated oscillator strengths using Bates & Damgaard method and experimental values of energy levels from the reference of Kramida at all.
Comparison: experimental values of energy levels of Kramida at all. and calculated oscillator strengths using Bates & Damgaard method. We found that the difference in Stark width and shift is within 1 - 3%. This means that the Bates & Damgaard method for oscillator strengths calculations in the case of B IV transitions is adequate.
Virtual Atomic and Molecular Data Centrehttp://www.vamdc.eu
SCSLSA Banja Koviljača 13.05.2013
Conclusion
http://www.vamdc.org
SCSLSA Banja Koviljača 13.05.2013
AcknowledgmentsProject 176002, supported by the Ministry of Education, Science
and Technological development of Serbia
COST scientific programme on The Chemical Cosmos: Understanding Chemistry in Astronomical Environments
Partial financial support from Technical University – Sofia
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SCSLSA Banja Koviljača 13.05.2013
References
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SCSLSA Banja Koviljača 13.05.2013