2019A&A...627A..85Z


Query : 2019A&A...627A..85Z

2019A&A...627A..85Z - Astronomy and Astrophysics, volume 627A, 85-85 (2019/7-1)

Probing the initial conditions of high-mass star formation. III. Fragmentation and triggered star formation.

ZHANG C.-P., CSENGERI T., WYROWSKI F., LI G.-X., PILLAI T., MENTEN K.M., HATCHELL J., THOMPSON M.A. and PESTALOZZI M.R.

Abstract (from CDS):

Context. Fragmentation and feedback are two important processes during the early phases of star formation. Aims. Massive clumps tend to fragment into clusters of cores and condensations, some of which form high-mass stars. In this work, we study the structure of massive clumps at different scales, analyze the fragmentation process, and investigate the possibility that star formation is triggered by nearby HII regions. Methods. We present a high angular resolution study of a sample of massive proto-cluster clumps G18.17, G18.21, G23.97N, G23.98, G23.44, G23.97S, G25.38, and G25.71. Combining infrared data at 4.5, 8.0, 24, and 70µm, we use a few arcsecond resolution, radiometer and millimeter inteferometric data taken at 1.3cm, 3.5mm, 1.3mm, and 870µm to study their fragmentation and evolution. Our sample is unique in the sense that all the clumps have neighboring HII regions. Taking advantage of that, we tested triggered star formation using a novel method where we study the alignment of the center of mass traced by dust emission at multiple scales. Results. The eight massive clumps, identified based on single-dish observations, have masses ranging from 228 to 2279M within an effective radius of Reff∼0.5pc. We detect compact structures towards six out of the eight clumps. The brightest compact structures within infrared bright clumps are typically associated with embedded compact radio continuum sources. The smaller scale structures of Reff∼0.02pc observed within each clump are mostly gravitationally bound and massive enough to form at least a B3-B0 type star. Many condensations have masses larger than 8M at a small scale of Reff∼0.02pc. We find that the two infrared quiet clumps with the lowest mass and lowest surface density with <300M do not host any compact sources, calling into question their ability to form high-mass stars. Although the clumps are mostly infrared quiet, the dynamical movements are active at clump scale (∼1pc). Conclusions. We studied the spatial distribution of the gas conditions detected at different scales. For some sources we find hints of external triggering, whereas for others we find no significant pattern that indicates triggering is dynamically unimportant. This probably indicates that the different clumps go through different evolutionary paths. In this respect, studies with larger samples are highly desired.

Abstract Copyright: © ESO 2019

Journal keyword(s): stars: formation - techniques: interferometric - ISM: clouds - methods: observational

VizieR on-line data: <Available at CDS (J/A+A/627/A85): table1.dat-table6.dat list.dat fits/*>

Simbad objects: 21

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Number of rows : 21
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5811 1
2 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 3057 2
3 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4351 2
4 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1255 1
5 NGC 6334 HII 17 20 53 -36 07.9           ~ 683 0
6 NGC 6357 OpC 17 24 44 -34 12.2           ~ 274 0
7 QSO B1741-038 QSO 17 43 58.85613537 -03 50 04.6167326     20.40 17.98   ~ 549 1
8 MMB G011.109-00.114 Y*O 18 10 28.25 -19 22 29.1           ~ 56 0
9 AGAL G018.174-00.299 smm 18 25 07.560 -13 14 29.99           ~ 8 0
10 AGAL G018.214-00.342 Y*O 18 25 22 -13 13.6           ~ 12 0
11 AGAL G023.979+00.149 Y*O 18 34 27.8 -07 53 36           ~ 10 0
12 AGAL G023.965+00.139 Y*O 18 34 29.0 -07 54 35           ~ 9 0
13 AGAL G023.437-00.182 smm 18 34 39 -08 31.6           ~ 27 0
14 AGAL G023.964-00.109 cor 18 35 22.2 -08 01 24           ~ 21 1
15 AGAL G025.709+00.044 smm 18 38 03.3789 -06 24 00.908           ~ 19 0
16 AGAL G025.382-00.147 Y*O 18 38 08.167 -06 46 53.19           ~ 25 0
17 AGAL G028.344+00.061 cor 18 42 50.45 -04 03 17.7           ~ 86 0
18 AGAL G029.976-00.047 cor 18 46 12.25 -02 39 05.9           ~ 27 0
19 NAME Cyg X BL? 20 30 04.7973633 +40 51 36.002197           ~ 848 1
20 EM* MWC 349 ** 20 32 45.499080 +40 39 36.74124   15.88 13.15 12.13   Bep 802 0
21 [CFR2000] G011.11-0.12 P6 smm ~ ~           ~ 7 0

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