J/A+A/460/783 Barnes-Evans relations for dwarfs (Beuermann, 2006)
Barnes-Evans relations for dwarfs with an application to the determination of
distances to cataclysmic variables.
Beuermann K.
<Astron. Astrophys. 460, 783 (2006)>
=2006A&A...460..783B 2006A&A...460..783B
ADC_Keywords: Models ; Stars, dwarfs
Keywords: stars: fundamental parameters - stars: distances -
stars: dwarf novae - stars: novae, cataclysmic variables -
Abstract:
Barnes-Evans type relations provide an empirical relationship between
the surface brightness of stars and their color. They are widely used
for measuring the distances to stars of known radii, as the Roche-lobe
filling secondaries in cataclysmic variables (CVs). The calibration of
the surface brightness of field dwarfs of near-solar metalicity with
spectral types A0 to L8 covers all secondary spectral types detectable
in CVs and related objects and will aid in the measurement of their
distances. The calibrations are based on the radii of field dwarfs
measured by the Infrared Flux Method and by interferometry. Published
photometry is used and homogenized to the Cousins Rc and Ic and the
CIT JHK photometric systems. The narrow band surface brightness at
7500Å is based on our own and published spectrophotometry. Care is
taken to select the dwarfs for near-solar metalicity, appropriate to
CVs, and to avoid errors caused by unrecognized binarity.
Description:
Table 2 contains the parameters of the polynomial fits to the
observationally determined Barnes-Evans relations vs. color V-K or
spectral type represented by the quantity X.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 20 Parameters of polynomial fits of surface
brightness vs. V-K or spectral type
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Line Line number
4- 9 A6 --- DepV Dependant variable (1)
11- 13 A3 --- X [X V-K] Independent variable used
in polynomial fit (2)
15- 18 F4.1 --- Rangel Range of independant variable (lower limit)
20- 23 F4.1 --- Rangeu Range of independant variable (upper limit)
25- 28 A4 --- SpTypel Lower spectral type range
30- 33 A4 --- SpTypeu Upper spectral type range
35- 42 F8.3 --- a0 a0 coefficient of polynomial fit (2)
44- 52 F9.5 --- a1 a1 coefficient of polynomial fit (2)
54- 62 F9.6 --- a2 ? a2 coefficient of polynomial fit (2)
64- 74 F11.8 --- a3 ? a3 coefficient of polynomial fit (2)
76- 86 E11.6 --- a4 ? a4 coefficient of polynomial fit (2)
88- 98 E11.6 --- a5 ? a5 coefficient of polynomial fit (2)
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Note (1): Dependant variables as follows:
S_V = Surface brightness in V band
S_Rc = Surface brightness in Rc band
S_Ic = Surface brightness in Ic band
S_K = Surface brightness in K band
F_7500 = Narrow-band (7500Å) surface brightness
F_TiO = Flux deficiency in the TiO band structure around at 7165Å
(difference between the mean surface fluxes in
the bands 7450-7550Å and 7140-7190Å)
Note (2): Polynomial fit of the surface brightness:
SK=a0+a1(X)+a2(X)2+a3(X)3+a4(X)4+a5(X)5
The spectral type variable X increases with effective temperature,
and is related to the subtypes by:
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X range Spectral Subtype
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[1,10] L(10-X)
[11,20] M(20-X)
[21,28] K(28-X)
[29,38] G(38-X)
[39,48] F(48-X)
[49,58] A(58-X)
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Acknowledgements:
Klaus Beuermann, beuermann(at)uni-sw.gwdg.de
(End) Patricia Vannier [CDS] 21-Sep-2006