Empirical Calibration of the Near-IR Ca II Triplet


Project Summary

This project is dedicated to the empirical calibration of the Ca II triplet and stellar population synthesis modelling. For this purpose, we make use of a new stellar library of 706 stars in the near-IR spectral range (from 8348 Å to 9020 Å with a FWHM of 1.5 Å) which spans a wide range of updated atmospheric parameters. We have defined a new set of near-IR indices which mostly overcome the limitations of previous definitions, being specially suited for the measurement of the Ca II triplet strength corrected for the contamination with Paschen lines. Empirical fitting functions for the above indices have been derived and, together with the full stellar library, have been implemented into an evolutionary stellar populations synthesis model. This allows us to predict both the Ca II triplet strength on the basis of the fitting functions and full near-IR spectra in the range of the library for stellar populations of a wide range of ages and metallicities.




Publications

Paper I : Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition.

Paper II : Empirical calibration of the near-IR Ca II triplet - II. The atmospheric parameters.

Paper III : Empirical calibration of the near-IR Ca II triplet - III. Fitting functions.

Paper IV : Empirical calibration of the near-IR Ca II triplet - IV. The stellar population synthesis modelling.




Available at this web site

The spectra of the whole Stellar Library.

A Database containing full information for the stars (atmospheric parameters, near-IR line-strength indices, etc.)

Free Software for measuring and predicting the near-IR line-strength indices in stars and integrated stellar populations.