%0 Journal Article
%A Gorgas García, Francisco Javier
%A Cardiel López, Nicolás
%A Pedraz, S.
%A González, J. J.
%T Empirical calibration of the λ4000 Å break
%D 1999
%@ 0365-0138
%U https://hdl.handle.net/20.500.14352/59918
%X Empirical fitting functions, describing the behaviour of the λ4000 Å break, D_4000, 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.
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