NGC-7129 FIRS-2 - AN INTERMEDIATE-MASS COUNTERPART OF CLASS-0 OBJECTS

We present JCMT (sub)millimetre observations of the young source NGC 7 129 FIRS 2 and HIRAS maps of the whole NGC 7129 region. The total inte grated luminosity of FIRS 2 is approximate to 430 L.. Its spectral ene rgy distribution is described by a single-temperature grey body with T = 35 K and beta = 0.9. The total mass is found to be similar to 6 M.. These and other properties indicate that FIRS 2 is an intermediate-ma ss counterpart of the low-mass Class 0 protostellar objects; in this s ense, FIRS 2 is probably the youngest intermediate-mass object we know at present. The far-infrared emission of NGC 7129 is dominated by two sources: FIRS 1, which is located toward the HAeBe star LkH alpha 234 , and FIRS 2. The cavity observed in the optical NGC 7129 reflection n ebulosity and in radio emission lines is clearly observed in the HIRAS maps, particularly in the 25 mu m band. The total estimated luminosit y of the region is approximate to 4.5 10(3) L., consistent with the id ea that the dust is heated by the cluster of HAeBe stars in NGC 7129.