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


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.26CET06:06:19

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.

KUMAR M.S.N., FERNANDES A.J.L., HUNTER T.R., DAVIS C.J. and KURTZ S.

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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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 RAFGL 5123 FU* 04 31 34.07736 +18 08 04.9020           K3V/M3III 815 0
2 IRAS 07427-2400 mul 07 44 51.9 -24 07 41           ~ 55 0
3 WISE J074451.99-240742.1 mul 07 44 51.997 -24 07 42.11           ~ 64 0
4 GAL 005.88-00.41 HII 18 00 30.388 -24 04 00.20           ~ 301 0
5 IRAS 20126+4104 Y*O 20 14 25.8816186803 +41 13 36.869078243           B2.5-B0.5 399 0
6 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 949 0

    Equat.    Gal    SGal    Ecl

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2020.10.26-06:06:19

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