CONDITIONS IN THE Z=0.692 ABSORBER TOWARD 3CR-286

We present HST/FOS1 ultraviolet and ground-based optical spectra of th e z = 0.692 21 cm absorption system in the QSO 3CR 286. The strength o f the damped Ly alpha absorption implies an H I column density, N(H I) approximate to 2 x 10(21) cm(-2). We derive a high spin temperature f or the H I gas, T-s greater than or similar to 10(3) K, as has been fo und for other high-redshift 21 cm absorbing systems; at least 80% of t he H I is hotter than 1200 K. Curve-of-growth analysis yields Mg+ and Fe+ abundances which are similar to 1-2 dex below solar values; the Ca + abundance is even lower implying some depletion onto dust grains. Th e H-2 fraction is not high. We speculate that the high inferred T-s fo r the gas may reflect continuing active star formation at the 5-8 Gyr look-back time to the absorbing galaxy.