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Astron. Astrophys. 326, 1044-1054

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Photometric versus empirical surface gravities
of eclipsing binaries*

C. Jordi1, I. Ribas1, J. Torra1, and A. Giménez2

1Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Avda. Diagonal 647, E-08028 Barcelona, Spain
2LAEFF (INTA-CSIC), Apartado 50727, E-28080 Madrid, Spain

Received 18 March 1997 / Accepted 20 May 1997


Systematic differences in photometric stellar surface gravity determination are studied by means of the comparison with empirical values derived from detached double-lined eclipsing binaries. Photometric gravities were computed using Moon & Dworetsky (1985) grids based on Kurucz (1979) atmosphere models, and empirical gravities were taken from Andersen (1991). Individual Strömgren colours and FORMULA indices of each component of the binary system have to be taken into account to correctly analyze the observed differences. A compilation of data on a sample containing 30 detached double-lined eclipsing binaries with accurate ( FORMULA 1-2%) determination of mass and radius and available FORMULA photometric data is also presented.

Correction of the differences in terms of Teff and FORMULA for the range 11000 K FORMULA 20000 K reduces the mean residuals from 0.13 dex to 0.07 dex. For the range 7000 K FORMULA 8500 K, the consideration of metallicity effects by means of FORMULA index improves the accuracy from 0.20 dex to 0.09 dex.

Key words: stars: fundamental parameters - stars: binaries: eclipsing - stars: early-type - stars: late-type

*Table 5 is also available in electronic form from CDS via anonymous ftp at, and by e-mail request to C. Jordi at carme@facjn0.am.ub.es

Send offprint requests to: C. Jordi

© European Southern Observatory (ESO) 1997

Online publication: October 1, 1997
Last change: April 8, 1998