J/AJ/106/2096 Limb-darkening coefficients in binaries (Van Hamme 1993)
New limb-darkening coefficients for modeling binary star light curves
VAN HAMME W.
<Astron. J. 106, 2096 (1993)>
=1993AJ....106.2096V 1993AJ....106.2096V
ADC_Keywords: Binaries, eclipsing; Models, atmosphere
Abstract:
We present monochromatic, passband-specific, and bolometric
limb-darkening coefficients for a linear as well as nonlinear
logarithmic and square root limb-darkening laws. These coefficients,
including the bolometric ones, are needed when modeling binary star
light curves with the latest version of the Wilson-Devinney light curve
program. We base our calculations on the most recent ATLAS stellar
atmosphere models for solar chemical composition stars with a wide
range of effective temperatures and surface gravities. We examine how
well various limb-darkening approximations represent the variation of
the emerging specific intensity across a stellar surface as computed
according to the model. For binary star light curve modeling purposes,
we propose the use of a logarithmic or a square root law. We design
our tables in such a manner that the relative quality of either law
with respect to another can be easily compared. Since the computation
of bolometric limb-darkening coefficients first requires monochromatic
coefficients, we also offer tables of these coefficients (at 1221
wavelength values between 0.09 nm and 160 µm) and tables of
passband-specific coefficients for commonly used photometric filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 79 410 Bolometric limb-darkening coefficients
table2 87 6970 Passband-specific limb-darkening coefficients
table3a 29 410 Models parameters
table3b 70 410 Bolometric coefficients
table3c 79 466367 Monochromatic coefficients
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Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 3 I3 --- Model Model number
4- 9 I6 K Teff Effective temperature
10- 14 F5.1 [cm/s2] log(g) Logarithm of the surface gravity
15- 22 F8.3 --- xBol Bolometric linear limb-darkening coefficient x
25- 30 F6.4 --- QBol Quality factor (1)
32- 39 F8.3 --- xLog Logarithmic law x coefficient
40- 46 F7.3 --- yLog Logarithmic law y coefficient
49- 54 F6.4 --- QLog Quality factor (1)
56- 63 F8.3 --- xSqu Square root law x coefficient
64- 70 F7.3 --- ySqu Square root law y coefficient
73- 78 F6.4 --- QSqu Quality factor (1)
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Note (1): see below on table3b
Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 3 I3 --- Model Model number
4- 9 I6 K Teff Effective temperature
10- 14 F5.1 [cm/s2] log(g) Logarithm of the surface gravity
17- 20 A4 --- Pass Passband (2)
24- 28 F5.3 --- xLin Linear limb-darkening coefficient
31- 36 F6.4 --- QLin Quality factor (1)
42- 46 F5.3 --- xLog Logarithmic law x coefficient
48- 53 F6.3 --- yLog Logarithmic law y coefficient
56- 61 F6.4 --- QLog Quality factor (1)
66- 71 F6.3 --- xSqu Square root law x coefficient
73- 78 F6.3 --- ySqu Square root law y coefficient
81- 86 F6.4 --- QSqu Quality factor (1)
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Note (1): see below on table3b
Note (2): The passbands are:
Johnson : UBVRIJKLMN
Cousins : Ic Rc
Stroemgren : uvby
bolo = bolometric
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Byte-by-byte Description of file: table3a
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Bytes Format Units Label Explanations
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1- 3 I3 --- Model Model number
6- 10 I5 K Teff Effective temperature
12- 14 F3.1 [cm/s2] log(g) Logarithm of the surface gravity
16- 19 F4.2 Sun A Abundance (always solar abundance)
22- 24 F3.1 km/s Vturb Microturbulent velocity
26- 29 F4.2 --- l/H []? Convective parameter
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Byte-by-byte Description of file: table3b table3c
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Bytes Format Units Label Explanations
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1- 3 I3 --- Model Model number
5- 15 F11.2 nm lambda []? Wavelength
17- 21 F5.3 --- xBol Linear limb-darkening coefficient
23- 28 F6.4 --- QBol Quality factor (1)
30- 34 F5.3 --- xLog Logarithmic law x coefficient
36- 41 F6.3 --- yLog Logarithmic law y coefficient
43- 48 F6.4 --- QLog Quality factor (1)
50- 55 F6.3 --- xSqu Square root law x coefficient
57- 62 F6.3 --- ySqu Square root law y coefficient
64- 69 F6.4 --- QSqu Quality factor (1)
71- 79 E9.3 mW/m2/sr/nm I ? Intensity, I(lambda, mu=1)
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Note (1): Quality factor Q defined as (all parameters refer to
monochromatic values):
Q={sum(for i=1 to 17)[D(mui)-D'(mui)]/(17-m)}1/2
where D(mu) = I(mu)/I(1)
D'(mu) = I'(mu)/I'(1)
and I(mu) is the theoretical specific intensity
I'(mu) is the specific intensity according to the limb-darkening
approximation
This number may help in choosing which limb-darkening law to use in
any particular case
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Origin: AAS CD-ROM series, Volume 1, 1993
(End) Patricia Bauer [CDS] 30-Jun-1994