Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121
We have observed the central region of the infrared-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(J = 1-0), 13CO(J = 1-0), and C18O(J = 1-0) line emission and with Spitzer at midinfrared wavelengths. Five massive outflows from two cloud cores were discovered. Three outflows are centered on or near an ultracompact (UC) H II region (G34.4+0.23), while the remaining two outflows originate from the millimeter core G34.4+0.23 MM. Modeling of the spectral energy distributions of the mid-infrared sources identified 31 young stellar objects in the filament with a combined stellar mass of âˆ¼ 127 Â± 27 MâŠ™. An additional 22 sources were identified as probable cluster members based on the presence of strong 24 Î¼m emission. The total star formation efficiency in the G34.4 cloud filament is estimated to be âˆ¼7%, while the massive and intermediate-mass star formation efficiency in the entire cloud filament is estimated to be roughly 2%. A comparison of the gravitational binding energy with the outflow kinetic energy suggests that the compact core containing G34.4+0.23 MM is being destroyed by its molecular outflows, whereas the outflows associated with the more massive core surrounding the G34.4 UC H II region are not likely to totally disrupt the cloud. In addition, a qualitative evaluation of the region appears to suggest that stars in this region may have formed in two stages: first lower mass stars formed and then, a few Myr later, the more massive stars began to form. Â© 2007. The American Astronomical Society. All rights reserved.
|Título según WOS:||Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121|
|Título según SCOPUS:||Molecular outflows and a mid-infrared census of the massive star formation region associated with IRAS 18507+0121|
|Título de la Revista:||ASTROPHYSICAL JOURNAL|
|Editorial:||IOP PUBLISHING LTD|
|Fecha de publicación:||2007|
|Página de inicio:||464|