2003A&A...412..175K

A multi-wavelength study of IRAS 07427-2400 in line and continuum emission was conducted to investigate the nature of a H₂ v=1-0 S(1) line emitting feature around this ultra-compact HII region. High resolution 3.6 cm continuum observations from the Very Large Array and 350µm continuum observations from the Caltech Submillimeter Observatory, combined with archival far-infrared data of IRAS 07427-2400 show a flux density distribution indicating a luminous ∼0.1km/s/arcsec. New CO J=3-2 maps of the region are presented which reveal a massive molecular outflow from the IRAS source. We argue that the H₂ feature arises in a disk/envelope around IRAS 07427-2400 and not in an outflow. We present a near-infrared HK band spectrum of the H₂ features that shows several ro-vibrational emission lines of H₂ and [FeII]. Analysis of the line ratios indicates that the line emission is shock-excited and not due to fluorescence. We estimate an excitation temperature of ∼1600K and an average extinction of A_v∼11mag to the H₂ feature. The line fluxes yield a mass accretion rate of {dot}(M)∼2.6±0.9x10^–2M_☉/yr and a lifetime of ∼5360±1200yr resulting in a disk/envelope mass of 140±50M_☉. The resulting Jeans Mass of 2420M_☉ indicates that the disk/envelope will not undergo fragmentation. IRAS 07427-2400 represents one of the most massive YSOs known to date forming by means of accretion.