Deeply Embedded Objects and Shocked Molecular Hydrogen: The Environment of the FU Orionis Stars RNO 1B/1C

We present Spitzer IRAC and IRS observations of the dark cloud L1287. The mid-infrared (MIR) IRAC images show deeply embedded infrared sources in the vicinity of the FU Orionis objects RNO 1B and RNO 1C, suggesting their association with a small young stellar cluster. We resolve for the first time the MIR point source associated with IRAS 00338+6312, which is a deeply embedded intermediate-mass protostar driving a known molecular outflow. The IRAC colors of all the objects are consistent with those of young stars ranging from deeply embedded Class 0/I sources to Class II objects, some of which appear to be locally reddened. The two IRS spectra show strong absorption bands due to ices and dust particles, confirming that the circumstellar environment around RNO 1B/1C has a high optical depth. Additional hydrogen emission lines from pure rotational transitions are superposed on the spectra. Given the outflow direction, we attribute these emission lines to shocked gas in the molecular outflow powered by IRAS 00338+6312. The derived shock temperatures are in agreement with predictions for high-velocity C-type shocks.