2014A&A...570A..51S


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.21CEST18:28:48

2014A&A...570A..51S - Astronomy and Astrophysics, volume 570A, 51-51 (2014/10-1)

The physical conditions in IRDC clumps from Herschel/HIFI observations of H2O.

SHIPMAN R.F., VAN DER TAK F.F.S., WYROWSKI F., HERPIN F. and FRIESWIJK W.

Abstract (from CDS):

The earliest phases of high-mass star formation are poorly understood. Our goal is to determine the physical conditions and kinematic structure of massive starforming cloud clumps. We analyse H2O 557GHz line profiles observed with HIFI toward four positions in two infrared-dark cloud clumps. By comparison with ground-based C17O, N2H+, CH3OH, and NH3 line observations, we constrain the volume density and kinetic temperature of the gas and estimate the column density and abundance of H2O and N2H+. The observed water lines are complex with emission and absorption components. The absorption is redshifted and consistent with a cold envelope, while the emission is interpreted as resulting from proto-stellar outflows. The gas density in the clumps is ∼107cm–3. The o-H2O outflow column density is 0.3-3.0x1014cm–2. The o-H2O absorption column density is between 1.5x1014 and 2.6x1015cm–2 with cold o-H2O abundances between 1.5x10–9 and 3.1x10–8. All clumps have high gas densities (∼107cm–3) and display infalling gas. Three of the four clumps have outflows. The clumps form an evolutionary sequence as probed by H2O N2H+, NH3, and CH3OH. We find that G28-MM is the most evolved, followed by G11-MM and then G28-NH3. The least evolved clump is G11-NH3 which shows no signposts of starformation; G11-NH3 is a high-mass pre-stellar core.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: massive - ISM: clouds - evolution

VizieR on-line data: <Available at CDS (J/A+A/570/A51): list.dat fits/*>

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 653 0
2 GAL 010.47+00.03 HII 18 08 38.4 -19 51 52           ~ 105 0
3 MMB G011.109-00.114 Y*O 18 10 28.4449 -19 22 38.782           ~ 44 0
4 [CCE98b] 011.11-0.12 Cld 18 10.5 -19 23           ~ 82 1
5 NAME Dragon Nebula DNe 18 42 50.6 -04 03 30           ~ 98 0
6 [PWC2006] NH3 G28.34+0.06 P2 cor 18 42 52.4 -03 59 54           ~ 18 0
7 [MSL2003] W43-MM1 cor 18 47 47.0 -01 54 28           ~ 83 0
8 W 51 SNR 19 23 50 +14 06.0           ~ 1119 1
9 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 928 0
10 [PWC2006] NH3 G28.34+0.06 P3 Cld ~ ~           ~ 2 0
11 [PWC2006] NH3 G11.11-0.12 P2 smm ~ ~           ~ 4 0

    Equat.    Gal    SGal    Ecl

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2019.10.21-18:28:48

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