Synthetic HB generator:

readme file

last modification: 12 Feb 2011


This Horizontal Branch Synthesis Program calculates the photometric properties of HB stars in old stellar populations. The code employs the theoretical tracks provided in the BaSTI archive. At the moment the HB mass distribution is assumed to be Gaussian, while photometric errors are not yet taken into account.

The user needs to specify the following parameters:
a) mean HB mass;
b) 1sigma dispersion of the Gaussian Distribution;
c) metallicity;
d) heavy element mixture: scaled solar or alpha-enhanced;
e) the photometric system;

The output provides magnitudes and properties of the objects within the RR Lyrae instability strip. For stars located in the "OR" region - where both fundamental and first overtone pulsational mode can be stable - the code provides the fundamental mode pulsation period.

The output summarizes also the total number of blue HB stars - those located on the blue side of the RR Lyrae instability strip -, red HB stars - those located at an effective temperature lower than the Red Edge of the RR Lyrae instability strip, and Asymptotic Giant Branch stars.

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