Outflowing activity in the UCHII region G045.47+0.05

ORTEGA MARTIN E.; PARON, SERGIO; CICHOWOLSKI SILVINA; RUBIO, MONICA; DUBNER GLORIA

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2012

0004-6361

Aims. This work aims at investigating the molecular gas in the surroundings of the ultra-compact HII region G045.47+0.05 looking for evidence of molecular outflows.Methods. We carried out observations towards a region of 2′ ×2′ centered at RA=19h 14m 25.6s , dec.=+11◦ 09′ 27.6′′ (J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in the12CO J=3?2,13CO J=3?2, HCO+ J=4?3 and CS J=7?6 lines with an angular resolution of 22′′ . We complement these observations with public infrared data.Results. We characterize the molecular clump where G045.47+0.0 is em-bedded and estimate that it has a mass of about 104 M⊙ . The detection of the CS J=7?6 line emission in the region reveals that the ultra-compact HII region G045.47+0.0 has not completely disrupted the dense gas where it has been born. The HCO+ abundance observed towards G045.47+0.0 suggests the presence of molecular outflow activity in the region. From the analysis of the 12CO J=3?2 transition we re-port the presence of bipolar molecular outflows with a total mass of about 300 M⊙ .We derive a dynamical time (flow?s age) of about 105 yr for the outflow gas, in agreement with the presence of an ultra-compact HII region. We identify the 2MASS 19142564+1109283 source as the massive protostar candidate to be driving the molecular outflows. Based on the analysis of its spectral energy distribution we infer that it as an early B-type star of about 15 M⊙ .The results of this work support the scenario where the formation of mas-sive stars, at least up to early B-type stars, is similar to that of low mass stars.