SIMBAD references

2003A&A...412..175K - Astronomy and Astrophysics, volume 412, 175-184 (2003/12-2)

A massive disk/envelope in shocked H2 emission around an UCHII region.


Abstract (from CDS):

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 Av∼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.

Abstract Copyright:

Journal keyword(s): stars: formation - accretion: accretion disks - interstellar medium: jets and outflows - ISM: HII regions

Simbad objects: 6

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