Melchiors: a new library of 2000 stars with high-spectral fidelity

Libraries of stellar spectra have been used for a large variety of science cases, including population synthesis for galactic and extra-galactic studies, spectral classification and calibrations, studies of binaries, and data-driven sample for machine learning applications. To date, UVES-POP is the only very high resolution optical spectral library, offering reduced spectra for a few hundred objects from the Southern hemisphere. With the Melchiors spectral library, we are extending the sample, offering a finer coverage of all spectral-types and luminosity classes (including the Sun as a star), with a uniform collection of 3250+ echelle spectra of 2000+ bright stars obtained in the Northern hemisphere, with the MERCATOR-HERMES spectrograph, whose pipeline offers high quality data reduction products. We devised methods to correct for the instrumental response to approach the true shape of the spectral continuum, and a normalisation process to provide a homogeneous normalisation of the full spectral range for most of the objects. The Melchiors database is covering the full visible spectral range ([3800, 9000] Å) with high-resolution (R=85000) and with a median S/N reaching 200 in the V band. It includes instrumental and tellurics corrected, and normalised spectra. In addition, half of the stars have at least two exposures and a fraction of them are related to binarity. The Melchiors database is available at www.royer.se/melchiors.html