High resolution spectroscopy over 8500-8750 Å for GAIA ^*,**,***

II. A library of synthetic spectra for 7500 K

¹ Osservatorio Astronomico di Padova, Sede di Asiago, I-36012 Asiago
² Centro Interpardimentale Studi ed Attività Spaziali (CISAS “G. Colombo"), Università di Padova, Italy
³ CNR-GNA-Osservatorio Astronomico di Trieste Via Tiepolo 11, I-34131 Trieste, Italy

Send offprint request to: U. Munari, e-mail: munari@pd.astro.it

Received: 9 September 1999
Accepted: 4 October 1999

Abstract

We present a library of synthetic spectra characterized by , and   K computed at the same = 20000 resolving power of the observed spectra given in Paper I for 131 standard stars mapping the MKK spectral classification system. This range of parameters includes the majority of the galactic stars expected to dominate the GAIA target population, i.e. F-G-K-M type stars with metallicity ranging from that of the galactic globular clusters to Population I objects. Extension to > 7500 K will be given later on in this series. The 254 synthetic spectra presented here are based on Kurucz's codes and line data and have been computed over a more extended wavelength interval (7650-8750 Å) than that currently baselined for implementation on GAIA, i.e. the 8500-8750 Å. This last range is dominated by the near-IR Ca II triplet and the head of the Paschen series. The more extended wavelength range allows us to investigate the behaviour of other strong near-IR spectral features (severely contaminated by telluric absorptions in ground-based observed spectra) as the K I doublet (7664, 7699 Å), the Na I doublet (8183, 8194 Å) and the lines of Fe I multiplet N.60 at 8327 and 8388 Å. The synthetic spectra support our previous conclusions about the superior performance of the Paschen/Ca II 8500-8750 Å region in meeting the GAIA requirements when compared to other near-IR intervals of similar = 250 Å.