2013A&A...558A..69W


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST15:14:28

2013A&A...558A..69W - Astronomy and Astrophysics, volume 558A, 69-69 (2013/10-1)

Dense molecular cocoons in the massive protocluster W3 IRS 5: a test case for models of massive star formation.

WANG K.-S., BOURKE T.L., HOGERHEIJDE M.R., VAN DER TAK F.F.S., BENZ A.O., MEGEATH S.T. and WILSON T.L.

Abstract (from CDS):

Two competing models describe the formation of massive stars in objects like the Orion Trapezium. In the turbulent core accretion model, the resulting stellar masses are directly related to the mass distribution of the cloud condensations. In the competitive accretion model, the gravitational potential of the protocluster captures gas from the surrounding cloud for which the individual cluster members compete. With high resolution submillimeter observations of the structure, kinematics, and chemistry of the proto-Trapezium cluster W3 IRS5, we aim to determine which mode of star formation dominates. We present 354 GHz Submillimeter Array observations at resolutions of 1"-3" (1800-5400AU) of W3 IRS5. The dust continuum traces the compact source structure and masses of the individual cores, while molecular lines of CS, SO, SO2, HCN, H2CS, HNCO, and CH3OH (and isotopologues) reveal the gas kinematics, density, and temperature. The observations show five emission peaks (SMM1-5). SMM1 and SMM2 contain massive embedded stars (∼20M); SMM3-5 are starless or contain low-mass stars (<8M). The inferred densities are high, ≥107cm–3, but the core masses are small, 0.2-0.6M. The detected molecular emission reveals four different chemical zones. Abundant (X ∼ few 10–7 to 10–6) SO and SO2 are associated with SMM1 and SMM2, indicating active sulfur chemistry. A low abundance (5x10–8) of CH3OH concentrated on SMM3/4 suggest the presence of a hot core that is only just turning on, possibly by external feedback from SMM1/2. The gas kinematics are complex with contributions from a near pole-on outflow traced by CS, SO, and HCN; rotation in SO2, and a jet in vibrationally excited HCN. The proto-Trapezium cluster W3 IRS5 is an ideal test case to discriminate between models of massive star formation. Either the massive stars accrete locally from their local cores; in this case the small core masses imply that W3 IRS5 is at the very end stages (1000yr) of infall and accretion, or the stars are accreting from the global collapse of a massive, cluster forming core. We find that the observed masses, densities and line widths observed toward W3 IRS 5 and the surrounding cluster forming core are consistent with the competitive accretion of gas at rates of {dot}(M)∼10–4M/yr by the massive young forming stars. Future mapping of the gas kinematics from large to small scales will determine whether large-scale gas inflow occurs and how the cluster members compete to accrete this material.

Abstract Copyright:

Journal keyword(s): stars: massive - stars: formation - ISM: kinematics and dynamics - ISM: individual objects: W3 IRS5

Nomenclature: Table 1: [WBH2013] SMMN (Nos SMM1-SMM5).

Simbad objects: 32

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Number of rows : 32

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 QSO B0133+476 QSO 01 36 58.59480585 +47 51 29.1000445     18.0 19.25 15.21 ~ 446 1
2 NAME W 3 SMS 1 smm 02 25 40.3 +62 05 53           ~ 10 0
3 [WBH2013] SMM4 smm 02 25 40.431 +62 05 51.36           ~ 2 0
4 [WBZ2012] SMS1-MM2 mm 02 25 40.48 +62 05 50.5           ~ 2 0
5 [WBH2013] SMM5 smm 02 25 40.50 +04 00 00.0           ~ 2 0
6 [WBH2013] SMM3 smm 02 25 40.509 +62 05 50.41           ~ 2 0
7 NAME W3 IRS 5 Y*O 02 25 40.54 +62 05 51.4           B1 329 0
8 [RBM2008] MM3 mm 02 25 40.660 +62 05 51.95           ~ 3 0
9 [VTD2005] Q1 ? 02 25 40.6604 +62 05 51.822           ~ 3 0
10 [VTD2005] K3 Rad 02 25 40.6660 +62 05 52.345           ~ 9 0
11 [MWC2005] NIR 2 Rad 02 25 40.6711 +62 05 51.920           ~ 12 0
12 [WBH2013] SMM2 smm 02 25 40.679 +62 05 51.89           ~ 2 0
13 [RBM2008] MM2 mm 02 25 40.680 +62 05 51.53           ~ 4 0
14 [RBM2008] MM5 mm 02 25 40.680 +62 05 51.85           ~ 3 1
15 [VTD2005] MIR 1 IR 02 25 40.7 +62 05 52           ~ 8 0
16 [WBZ2012] SMS1-MM1 mm 02 25 40.77 +62 05 52.3           ~ 2 0
17 [RBM2008] MM1 mm 02 25 40.770 +62 05 52.49           ~ 4 0
18 [WBH2013] SMM1 smm 02 25 40.779 +62 05 52.55           ~ 2 0
19 [MWC2005] NIR 1 Rad 02 25 40.79 +62 05 52.6           ~ 12 0
20 NAME W 3 IRS 5 Cluster Cl* 02 25 42 +62 06.1           ~ 72 1
21 3C 84 Sy2 03 19 48.1597607660 +41 30 42.114155434   13.10 12.48 11.09   ~ 3544 3
22 NAME Per Arm PoG 03 30 +45.0           ~ 1247 0
23 NAME OMC1 Ridge reg 05 35 13.4 -05 23 07           ~ 123 0
24 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1466 1
25 NGC 1985 RNe 05 37 47.8 +31 59 24           ~ 130 2
26 NGC 2264 OpC 06 40 58 +09 53.7     3.9     ~ 1587 1
27 3C 273 BLL 12 29 06.6996828061 +02 03 08.598846466   13.05 14.830 14.11   ~ 5316 1
28 SCAMPS G8.68-0.37 smm 18 06 23.24 -21 37 14.1           ~ 11 0
29 GAL 029.96-00.02 Y*O 18 46 03.7 -02 39 21           ~ 331 1
30 GAL 035.20-01.74 Y*O 19 01 47.0 +01 13 08           ~ 71 1
31 RAFGL 2591 Y*O 20 29 25.03656 +40 11 20.3316           ~ 570 0
32 3C 454.3 QSO 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2505 2

    Equat.    Gal    SGal    Ecl

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2020.07.04-15:14:28

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