J/A+AS/139/29 J/A+AS/139/29 Empirical calibration of the 4000 A break J Gorgas N Cardiel S Pedraz J J Gonzalez Astron. Astrophys. Suppl. Ser. 139 29 1999 1999A&AS..139...29G J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994) Stars, fundamental Effective temperatures Abundances, [Fe/H] stars: fundamental parameters galaxies: stellar content techniques: spectroscopic stars: atmospheres Empirical fitting functions, describing the behaviour of the {lambda}4000{AA} break in terms of effective temperature, metallicity and surface gravity, are presented. For this purpose, the break has been measured in 392 stars from the Lick/IDS Library. We have followed a very detailed error treatment in the reduction and fitting procedures, allowing for a reliable estimation of the break uncertainties. This calibration can be easily incorporated into stellar population models to provide accurate predictions of the break amplitude for, relatively old, composite systems. Table 1 lists the star sample, together with spectral types, adopted atmospheric parameters, break measurements, including errors, and residuals from the fitting functions.

HD HD (Cat. <III/135>) name --- Name Alternative name --- SpType Spectral type number=1 Sources for spectral types are, in order of preference: Worthey et al. (1994, Cat. <J/ApJS/94/687>)), Gorgas et al. (1993ApJS...86..153G), the Bright Star Catalog (Hoffleit & Jaschek, 1982, Cat. <V/50>) and the SIMBAD database. For the cluster stars (except for Coma and Hyades) we list positions in the HR diagram (SGB: subgiant branch; GB: giant branch; HB: horizontal branch, red clump stars; AGB: asymptotic giant branch) --- Teff Effective temperature K r_Teff Source for effective temperature number=2 Atmospheric parameters are taken from the electronic table of Worthey et al (1994, Cat. <J/ApJS/94/687>), with the following additional sources and modifications: 1: Cayrel de Strobel et al. (1997A&AS..124..299C, Cat. <III/200>) 2: Alonso et al. (1996, Cat. <J/A+AS/117/227>) 3: Gratton et al. (1996, Cat. <J/A+A/314/191>) 4: Mean from sources 1, 2 and 3 5: Mean from sources 1 and 2 6: Mean from sources 1 and 3 7: Thevenin (1998BICDS.in.press.T) 8: Marsakov and Shevelev (1995BICDS..47...13M, Cat. <V/89>) 9: Gies and Lambert (1992ApJ...387..673G) 10: Zakhozhaj and Shaparenko (1996, Cat. <J/other/KFNT/12.20>) 11: Dyck et al. (1996AJ....111.1705D) 12: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Gorgas et al. (1993ApJS...86..153G) (in terms of (V-K)) 13: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>) (in terms of T_eff_) 14: Computed from the index Fe5270 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>)) (in terms of T_eff_) 15: From spectral type using table III of Johnson (1966ARA&A...4..193J) 16: Extrapolation in the relation T_eff_ versus spectral type of Ridgway et al. (1980ApJ...235..126R) (these temperatures differ from those given by Worthey et al. (1994, Cat. <J/ApJS/94/687>)) --- log(g) Logarithm of gravity cm/s2 r_log(g) Source for logarithm of gravity number=2 Atmospheric parameters are taken from the electronic table of Worthey et al (1994, Cat. <J/ApJS/94/687>), with the following additional sources and modifications: 1: Cayrel de Strobel et al. (1997A&AS..124..299C, Cat. <III/200>) 2: Alonso et al. (1996, Cat. <J/A+AS/117/227>) 3: Gratton et al. (1996, Cat. <J/A+A/314/191>) 4: Mean from sources 1, 2 and 3 5: Mean from sources 1 and 2 6: Mean from sources 1 and 3 7: Thevenin (1998BICDS.in.press.T) 8: Marsakov and Shevelev (1995BICDS..47...13M, Cat. <V/89>) 9: Gies and Lambert (1992ApJ...387..673G) 10: Zakhozhaj and Shaparenko (1996, Cat. <J/other/KFNT/12.20>) 11: Dyck et al. (1996AJ....111.1705D) 12: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Gorgas et al. (1993ApJS...86..153G) (in terms of (V-K)) 13: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>) (in terms of T_eff_) 14: Computed from the index Fe5270 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>)) (in terms of T_eff_) 15: From spectral type using table III of Johnson (1966ARA&A...4..193J) 16: Extrapolation in the relation T_eff_ versus spectral type of Ridgway et al. (1980ApJ...235..126R) (these temperatures differ from those given by Worthey et al. (1994, Cat. <J/ApJS/94/687>)) --- [Fe/H] Metallicity Sun r_[Fe/H] Source for metallicity number=2 Atmospheric parameters are taken from the electronic table of Worthey et al (1994, Cat. <J/ApJS/94/687>), with the following additional sources and modifications: 1: Cayrel de Strobel et al. (1997A&AS..124..299C, Cat. <III/200>) 2: Alonso et al. (1996, Cat. <J/A+AS/117/227>) 3: Gratton et al. (1996, Cat. <J/A+A/314/191>) 4: Mean from sources 1, 2 and 3 5: Mean from sources 1 and 2 6: Mean from sources 1 and 3 7: Thevenin (1998BICDS.in.press.T) 8: Marsakov and Shevelev (1995BICDS..47...13M, Cat. <V/89>) 9: Gies and Lambert (1992ApJ...387..673G) 10: Zakhozhaj and Shaparenko (1996, Cat. <J/other/KFNT/12.20>) 11: Dyck et al. (1996AJ....111.1705D) 12: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Gorgas et al. (1993ApJS...86..153G) (in terms of (V-K)) 13: Computed from the indices Fe5270 and Fe5335 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>) (in terms of T_eff_) 14: Computed from the index Fe5270 using the fitting functions of Worthey et al. (1994, Cat. <J/ApJS/94/687>)) (in terms of T_eff_) 15: From spectral type using table III of Johnson (1966ARA&A...4..193J) 16: Extrapolation in the relation T_eff_ versus spectral type of Ridgway et al. (1980ApJ...235..126R) (these temperatures differ from those given by Worthey et al. (1994, Cat. <J/ApJS/94/687>)) --- D4000 4000 A break --- e_D4000 Error on 4000 A break number=3 Total random errors in the lambda 4000 A break measurements --- Res Residual from the fitting functions number=4 Residuals from the derived fitting functions (observed minus predicted) --- Runs Runs in which the star was observed number=5 Run number(s) in which the star was observed. Number of repeated observations within each run is giving in parenthesis --- Comm Comments on individual stars number=6 Stars not used to derive the empirical functions are marked with: a: Non cluster members (see Gorgas et al., 1993ApJS...86..153G) b: Lacking required atmospheric parameters c: Emission-line supergiant --- Javier Gorgas UCM Patricia Bauer CDS 1999May18Javier Gorgas <fjg@astrax.fis.ucm.es> J_A+AS_139_29.xml