Stellar Properties

Basic parameters of YSOs (effective temperature, gravity, luminosity, mass, radial and rotational velocity, elemental abundance) are of fundamental importance to infer their evolutionary stage and their kinematical properties. Their knowledge is also needed to relate the disc properties to the global properties of the central star (e.g. mass, age). Although most information is contained in the UV-to-NIR photospheric lines, the spectral analysis needs special care due to the rapid rotation and to accretion-related structures that affect the observed spectra. Among these are permitted and forbidden emission lines originating in the accretion funnels, winds and jets and the veiling of the photospheric spectrum caused by continuous emission from the accretion impact region in the UV/visible and from the disk in the NIR. Members of the JEDI team have developed specific codes (e.g. ROTFIT) allowing to simultaneously derive atmospheric stellar parameters from medium-high resolution optical/IR spectra thus obtaining accurate and homogeneous datasets for comparison with accretion and disc parameters. Specific techniques are also applied to high resolution spectra to disentangle the parameters for close binaries.