  We present high-resolution Chandra HETGS X-ray spectra of the classical T
Tauri star SU Aur. The quiescent X-ray emission is dominated by a 20-40 MK
plasma, which contrasts strongly with the cool 3 MK plasma dominating the X-ray
emission of the CTTS TW Hya. A large flare occurred during the first half of
our 100 ks observation, and we have modelled the emitting plasma both during
this flare and during the apparently quiescent periods. During the flare, an
extremely high temperature plasma component (at least 60 MK) accounts for the
bulk of the emission. There is an indication of the presence of Fe XXVI
emission at 1.78 Angstrom, which is maximally formed at 130 MK.
