J/A+A/460/783Barnes-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..783BADC_Keywords: Models ; Stars, dwarfsKeywords: 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:

FileName Lrecl Records Explanations

ReadMe 80 . This file table2.dat 98 20 Parameters of polynomial fits of surface brightness vs. V-K or spectral type

Byte-by-byte Description of file: table2.dat

Bytes Format Units Label Explanations

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)

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: S_{K}=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: --------------------------- X range Spectral Subtype --------------------------- [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) ---------------------------

Acknowledgements: Klaus Beuermann, beuermann(at)uni-sw.gwdg.de(End)Patricia Vannier [CDS] 21-Sep-2006

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