J/MNRAS/361/1102 Spectrum of ε Eri (Sim+, 2005)
Modelling the chromosphere and transition region of ε Eri (K2 V).
Sim S.A., Jordan C.
<Mon. Not. R. Astron. Soc., 361, 1102-1120 (2005)>
=2005MNRAS.361.1102S 2005MNRAS.361.1102S
ADC_Keywords: Stars, late-type ; Spectra, ultraviolet ; Models, atmosphere
Keywords: radiative transfer - stars: chromospheres -
stars: individual (eps Eridani) - stars: late-type
Abstract:
Measurements of ultraviolet line fluxes from Space Telescope Imaging
Spectrograph and Far-Ultraviolet Spectroscopic Explorer spectra of the
K2-dwarf eps Eri are reported. These are used to develop new emission
measure distributions and semi-empirical atmospheric models for the
chromosphere and lower transition region of the star. These models are
the most detailed constructed to date for a main-sequence star other
than the Sun. New ionization balance calculations, which account for
the effect of finite density on dielectronic recombination rates, are
presented for carbon, nitrogen, oxygen and silicon. The results of
these calculations are significantly different from the standard
Arnaud & Rothenflug ion balance, particularly for alkali-like ions.
The new atmospheric models are used to place constraints on possible
first ionization potential (FIP)-related abundance variations in the
lower atmosphere and to discuss limitations of single-component models
for the interpretation of certain optically thick line fluxes.
Objects:
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RA (2000) DE Designation(s)
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03 32 55.8 -09 27 30 eps Eri = HD 22049
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 57 Emission line fluxes measured from the STIS spectra
table2.dat 72 22 Fluxes for emission lines in the FUSE spectra
tablea.dat 82 16 Logarithmic ionization fractions computed for
C, N, O and Si
tableb.dat 36 178 Parameters for the atmospheric models A, B and C
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See also:
J/ApJ/612/481 : Optical brightness of ε Eri dust ring (Proffitt+, 2004)
J/A+A/416/281 : X-ray spectra of 4 cool stars (Sanz-forcada+, 2004)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Ion Ion
7 A1 --- n_Ion [a] Note (1)
9- 46 A38 --- Trans Transition
49- 56 F8.3 0.1nm lambda0 Rest wavelength (2)
57- 58 A2 --- n_lambda0 [bl] Note for blend (3)
59- 66 F8.3 10-16W/m2 Flux Flux at Earth
68- 72 F5.3 10-16W/m2 e_Flux rms uncertainty on Flux
74- 76 A3 --- n_Flux [bl?] Note for blend (3)
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Note (1): In table2:
a: Measured from 1-SiC spectra, else measured in the 1-LiF spectra
Note (2): The rest wavelengths are taken from:
Griesmann & Kling (2000ApJ...536L.113G 2000ApJ...536L.113G) [C IV and Si IV in table1]
Kaufman & Martin (993, J. Phys. Chem. Ref. Data, 22, 279) [S IV in table1]
Kurucz & Bell (1995, Atomic Line Data CD-ROM No. 23) [all other lines]
Note (3): line is part of a blend: in such cases the total measured
flux in the blend is given as an upper limit to the line flux.
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Byte-by-byte Description of file: tablea.dat
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Bytes Format Units Label Explanations
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1- 4 F4.2 K logTe Electron temperature
6- 10 F5.2 --- IfCII ?=- C II Ionization fraction (1)
12- 16 F5.2 --- IfCIII ?=- C III Ionization fraction (1)
18- 22 F5.2 --- IfCIV ?=- C IV Ionization fraction (1)
24- 28 F5.2 --- IfNIII ?=- N III Ionization fraction (1)
30- 34 F5.2 --- IfNIV ?=- N IV Ionization fraction (1)
36- 40 F5.2 --- IfNV ?=- N V Ionization fraction (1)
42- 46 F5.2 --- IfOIII ?=- O III Ionization fraction (1)
48- 52 F5.2 --- IfOIV ?=- O IV Ionization fraction (1)
54- 58 F5.2 --- IfOV ?=- O V Ionization fraction (1)
60- 64 F5.2 --- IfOVI ?=- O VI Ionization fraction (1)
66- 70 F5.2 --- IfSiII ?=- Si II Ionization fraction (1)
72- 76 F5.2 --- IfSiIII ?=- Si III Ionization fraction (1)
78- 82 F5.2 --- IfSiIV ?=- Si IV Ionization fraction (1)
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Note (1): --- when not computed.
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Byte-by-byte Description of file: tableb.dat
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Bytes Format Units Label Explanations
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1 A1 --- Model [A-C] Model
4- 11 F8.5 g/cm2 logmcol Column mass density,
14- 18 F5.3 K logTe Electron temperature
20- 24 F5.2 cm-3 logNe Electron number density
26- 30 F5.2 cm-3 logNH Hydrogen number density
32- 36 F5.2 km/s Vt Most-probable microturbulent velocity
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 18-Apr-2006