L1451-mm SiO line and CH_3_OH maser detections

Both the detection of this Class I maser and SiO line in L1451- mm support the presence of low velocity and compact outflow. The excitation conditions of the thermal lines of methanol are also compatible with shocks (H_2_ density of ~3{AA}*10^6^cm^-3^ and temperature larger than 40K). Although the presence of such low velocity outflow is theoretically predicted by some models of FHSC, these models also predict the shock temperature to be below 20K, i.e. not evaporating methanol.

In addition, the predicted velocities would not erode the grains and release silicon in the gas-phase. We then conclude that these new observations favor the hypothesis that L1451- mm would be at a very early proto-stellar stage launching an outflow nearly on the plan of the sky with a higher velocity that what is observed.