THE TEMPERATURE AND IONIZATION OF T-TAURI MICRO-JETS DARREN M. O’BRIEN 1 , PAULO J.V. GARCIA 2 , JONATHAN FERREIRA 3 , SYLVIE CABRIT 4 and LUC BINETTE 5 1 Centro de Astrof´ ısica da Universidade do Porto & Departamento de Matem´ atica Aplicada da Faculdade de Ciˆ encias do Porto, Portugal; E-mail: darren@astro.up.pt 2 Centro de Astrof´ ısica da Universidade do Porto & Faculdade de Engenharia da Universidade do Porto, Portugal 3 Laboratoire d’Astrophysique de Grenoble, France 4 LERMA, Observatoire de Paris, France 5 Instituto de Astronom´ ıa, Ciudad Universitaria, Mexico Abstract. The effects of phenomenological heating functions on the flow thermodynamics of cold T-Tauri disk winds are examined. Turbulent dissipation (mechanical) heating and a warm disk corona are invoked to heat the wind. The temperature and ionization evolution are solved for along the flow. The results allow the construction of synthetic observations; emission maps, forbidden line ratios, line fluxes and line profiles; and successfully reproduce a number of observed trends. Mechanical heating produces line ratios and fluxes that fit very well with observations. Invoking a warm disk corona successfully reproduces forbidden line profile low velocity components. Keywords: ISM: jets and outflows, stars: pre-main sequence, MHD, line, profiles, accretion disks, coronae 1. Introduction Collimated mass ejection in young T-Tauri stars (TTS) is observationally found to be correlated with the accretion process (e.g., Hartigan et al., 1995). It is cur- rently believed that magnetic forces are responsible for both high ejection efficiency ( ˙ M jet / ˙ M acc ∼ 0.01 − 0.1) and the high degree of collimation of these winds (e.g., Konigl and Pudritz, 2000; Shu et al., 2000). In the regime of cold MHD, ejection is only possible from the disk by magneto- centrifugal launching on field lines sufficiently inclined from the disk axis, as no thermal energy is available to power matter across the gravitational potential barrier. Disk winds from wide range in disk radii (Blandford and Payne, 1982; Ferreira, 1997; Ferreira, these proceedings) have produced sufficiently complete calculations of MHD solutions to allow quantitative comparisons with observations. Observationally, the information available from jets is in the form of emission lines, therefore to test models, synthetic observations must be generated. This is achieved by modelling the thermal evolution in the jet (Garcia et al., 2001a, hereafter Paper I; Safier, 1993; Shang et al., 2002; Ferro-Font´ an and G ´ omez de Castro, 2003). This work follows from that of Paper I, which modelled the thermal evolution in T-Tauri jets consistently with the jet dynamical approximation of cold MHD of Astrophysics and Space Science 292: 609–617, 2004. C  2004 Kluwer Academic Publishers. Printed in the Netherlands.