last modification: 16 May 2008

Dear Colleagues,
it is now more than 4 years that we are working on the BaSTI database, continuously adding new models and features, checking and comparing our results with independent calculations and empirical constraints, and amending our outputs whenever some issues are raised.

Just a couple of examples of this code of conduct have been the inclusion of models and isochrones transformed to additional photometric systems, and the recomputation of the alpha-enhanced models when it was pointed out in the literature the existance of a problem (completely independent of us) with the previous set of low-T alpha-enhanced opacity tables we (and other authors before us) had used.

The computation of the models and isochrones included in BaSTI involves an enormous effort in terms of time and resources. The number of computed evolutionary tracks and HB models is extremely large and many different dedicated machines have been used over the course of these years. Our way of performing the calculations has been to compute on different machines sets of models in different mass ranges. Very recently we have discovered, during a further check of some of the physics inputs in our code, that calculations for the mass range 1.1Mo - 2.5Mo (i.e. age range ~1.0-4.0 Gyr) -- all performed on the same computer -- have employed a previous test version of the code, not the final standard version that we have used for all other masses included in BaSTI. This causes an inconsistency in the results involving those masses when compared to the rest of the database.

This is an unfortunate occurrence, and we sincerely apologize with all users of our models. With such a large number of calculations involved, in spite of careful checks, these things may happen. We stress however that this problem is circumscribed only to the mass range 1.1Mo - 2.5Mo (i.e. age range ~1.0-4.0 Gyr).

In line with our policy of making public immediately our findings and amend the database, we have recomputed with the standard correct version of the code all models in that mass range (and recomputed isochrones when necessary) for all chemical compositions.

We are pleased to inform that the whole set (tracks, isochrones, tables, WEB tools) of evolutionary predictions for both the scaled-solar models and the alpha-enhanced ones has been already replaced with the updated one. We wish also to inform that the alpha-enhanced model predictions are now available also in the ACS photometric system.

Our best regards!!!