ISO spectroscopy of shocked gas in the vicinity of T Tauri

We present the results of ISO SWS and LWS spectroscopy of the young binary system T Tau. The spectrum shows absorption features due to H2O ice, CO2 ic e, gas-phase CO and amorphous silicate dust, which we attribute to the enve lope of T Tau S. We derive an extinction of A(V) = 17(m)4 +/- O(m)6 towards this source. Detected emission lines from H I arise in the same region whi ch is also responsible for the optical Hr lines of T Tau N. These lines mos t likely arise in a partially ionized wind. Emission from the infrared fine -structure transitions of [S I], [ArII], [Ne II], [Fe 11], [Si II], [O I] a nd [C II] was also detected, which we explain as arising in a approximate t o 100 km s(-1) dissociative shock in a fairly dense(5 x 10(4) cm(-3)) mediu m. Pure rotational and rovibrational emission from molecular hydrogen was d etected as well. We show the H-2 emission lines to be due to two thermal co mponents, of 440 and 1500 K respectively, which we attribute to emission fr om the dissociative shock also responsible for the atomic fine-structure li nes and a much slower (approximate to 35 km s(-1)) non-dissociative shock. The 1500 K component shows clear evidence for fluorescent UV excitation. Ad ditionally, we found indications for the presence of a deeply embedded (A(V ) > 40 degrees) source of warm Ha emission. We suggest that this component might be due to a shock, caused by either the outflow from T Tau S or by th e infall of matter on the circumstellar disk of T Tau S.