1. STARK BROADENING IN ASTROPHYSICS
Milan S. Dimitrijević1,2
and
Zoran Simić1
1. Astronomical Observatory, Belgrade,
Volgina 7, Serbia
2. Observatoire de Paris, Meudon Cedex, France

2. 1. INTRODUCTION

3. Spectral type and effective temperature of a star can be
determined by comparing its
spectrum with a standard spectrum
for a spectral type and effective temperature. In Fig. left are spectral types and right effective temperatures.

4. NEEDS FOR LARGE STARK BROADENING DATA SET
- DEVELOPMENT OF COMPUTERS
FOR EXAMPLE:
PHOENIX CODE FOR MODELLING OF STELLAR ATMOSPHERES INCLUDES A PERMANENTLY GROWING DATABASA WITH ATOMIC DATA FOR MORE THAN 500 MILLIONS TRANSITIONS
- SATELLITE BORNE SPECTROSCOPY

6. Example of advance of satellite born spectroscopy
Part of Chi Lupi spectrum obtained with International Ultraviolet explorer (IUE) and with Godhard High Resolution Spectrograph on Hubble telescope (GHRS). One can see how lines of trace elements become more and more important.

11. STARK BROADENING IS IMPORTANT FOR:
- PLASMAS IN ASTRONOMY
- LABORATORY PLASMAS
- PLASMA TECHNOLOGIES

12. PLASMAS IN ASTRONOMY
Stark broadening may be important for plasma conditions from
NEUTRON STARS T= K
Ne= cm-3, white dwarfs, hot stars, up to other extreme conditions :
FOR RADIO RECOMBINATION LINES FROM
H I (T=50K) AND H II (T=10000K) REGIONS Ne = cm-3

13. F. Paerels, 1997, ApJ, 476, L47
A possibility to obtain M and R of a neutron star from a spectral line profile
W = 163Zˉ¹(M⁄R²)²⁄³T²⁄³ eV
Gravitational shift ~ M/R

14. Radio recombination lines are emitted from interstellar clouds H I (T=30K) and H II (T=10000K) Ne = cm-3

15. INTERSTELLAR MOLECULAR CLOUDS
In interstellar molecular clouds, typical electron temperatures are around 30 K or smaller, and typical electron densities are 2-15 cmˉ³. In such conditions, free electrons may be captured (recombination) by an ion in very distant orbit with principal quantum number (n) values of several hundreds and deexcite in cascade to energy levels n-1, n-2,... radiating in radio domain. Such distant electrons are weakly bounded with the core and may be influenced by very weak electric microfield. Consequently, Stark broadening may be significant.

16. Since the influence of Stark broadening in a spectral series increases with the increase of the principal quantum number of the upper level, the contribution of Stark broadening may be important even in Solar spectrum.

19. WHITE DWARFS The first - 40 Еridani Herschel 31.01.1783
The second, Sirius B, 1862 Alvan Graham Clarck
The third 1917 Van Maanen
1950 a hundred
1999 around 2000
Sloan Digital Sky Survay more than 9000

20. WHITE DWARFS This will be the destiny of 97% of stars in our Galaxy
Small masses – helium core,
Average masses (majority of observed) – core of C and O
Big masses – core of O, Ne and Mg

21. White dwarfs
TRADITIONAL DIVISION
DA – HYDROGEN RICH
DB – HELIUM RICH

22. 1979 was discovered prototype of a new class of hot hydrogen defficient degenerate stars PG1159-035
McGraw J. T., Starrfield S., Liebert J., Green R. F. 1979, Proc. IAU Coll. 53: White dwarfs and variable degenerate stars, H. M. van Horn, V. Weidemann eds., Univ. of Rochester, 377

23. K. Werner, U. Heber, K. Hunger, 1991, A&A, 244, 437

24. PG K < Teff< K
The hotest PG star H
Teff = K
DO K < Teff < K
DB K < Teff < K He I
DQ K < Teff < K C2 Swan
band
DZ lines of metals, accretion
DC continuum

26. STARK BROADENING DATA ARE NEEDED IN ASTRONOMY FOR EXAMPLE FOR: `
STELLAR PLASMA DIAGNOSTIC
- ABUNDANCE DETERMINATIONS
- STELLAR SPECTRA MODELLING,
ANALYSIS AND SYNTHESIS
- CHEMICAL STRATIFICATION
- SPECTRAL CLASSIFICATION
- NUCLEAR PROCESSES IN STELLAR
INTERIORS
- RADIATIVE TRANSFER
- STELLAR OPACITIES

27. Line shapes enter in the models of radiative envelopes by the determination of the Rosseland optical depth .

36. Maximal (upper line) and minimal (lower line) of the ratio of equivalent widths for different stellar types. Maximal and minimal value of EWSt/EW0 are given for 38 considered Nd II lines.
THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 135: , 2001
STARK BROADENING EFFECT IN STELLAR ATMOSPHERES: Nd II LINES
L. C. POPOVIC , S. SIMIC,
N. MILOVANOVIC, M. S.DIMITRIJEVIC

37. R. Hamdi, N. Ben Nessib, N. Milovanović, L. Č. Popović, M. S
R. Hamdi, N. Ben Nessib, N. Milovanović, L. Č. Popović, M. S. Dimitrijević and S. Sahal-Brécho, MNRAS, 387, 871 (2008).
Si VI 2p4(3P)3s 2P- 2p4(3P)3p 2 Do (λ = 1226, 7Å)
DО WHITE DWARFS Teff = – K and log g = 8.

38. M. S. Dimitrijević, T. Ryabchikova, Z. Simić, L. Č. Popović and M
M. S. Dimitrijević, T. Ryabchikova, Z. Simić, L. Č. Popović and M. Dačić, Astron. Astrophys., 469, 681 (2007).
We investigated Stark broadening of Cr II lines in Ap star HD for which careful abundance and stratification analysis was performed by Kochukov et al , A&A, 460, 831. For this star Teff=9400 K, log g = 3.7. Code SYNTH3

40. SCP CALCULATIONS OF ELECTRON AND ION IMPACT WIDTHS AND SHIFTS OF SPECTRAL LINES

42. STARK-B http://stark-b.obspm.fr42

43. 43

46. Group for Astrophysical spectroscopy

47. LSST 8.4 m 30Тb/night petabits of data

51. THANK YOU FOR ATTENTION