2020A&A...642A..76Z

Query : 2020A&A...642A..76Z

2020A&A...642A..76Z - Astronomy and Astrophysics, volume 642A76-76 (2020/10-1)

Fragmentation of star-forming filaments in the X-shaped nebula of the California molecular cloud.

ZHANG G.-Y., ANDRE P., MEN'SHCHIKOV A. and WANG K.

Abstract (from CDS):


Context. Dense molecular filaments are central to the star formation process, but the detailed manner in which they fragment into prestellar cores is not well understood yet.
Aims. Here, we investigate the fragmentation properties and dynamical state of several star-forming filaments in the X-shaped nebula region of the California molecular cloud in an effort to shed some light on this issue.
Methods. We used multiwavelength far-infrared images from Herschel as well as the getsources and getfilaments extraction methods to identify dense cores and filaments in the region and derive their basic properties. We also used a map of 13CO(2-1) emission from the Arizona 10m Submillimeter Telescope (SMT) to constrain the dynamical state of the filaments.
Results. We identified ten filaments with aspect ratios of AR>4 and column density contrasts of C>0.5, as well as 57 dense cores, including two protostellar cores, 20 robust prestellar cores, 11 candidate prestellar cores, and 24 unbound starless cores. All ten filaments have roughly the same deconvolved full width at half maximum (FWHM), with a median value of 0.12±0.03pc, which is independent of their column densities ranging from <1021cm–2 to >1022cm–2. Two star-forming filaments (# 8 and # 10) stand out since they harbor quasi-periodic chains of dense cores with a typical projected core spacing of ∼0.15pc. These two filaments have thermally supercritical line masses and are not static. Filament 8 exhibits a prominent transverse velocity gradient, suggesting that it is accreting gas from the parent cloud gas reservoir at an estimated rate of ∼40±10M☉/Myr/pc. Filament 10 includes two embedded protostars with outflows and it is likely at a somewhat later evolutionary stage than filament 8. In both cases, the observed (projected) core spacing is similar to the filament width and significantly shorter than the canonical separation of ∼4 times the filament width predicted by classical cylinder fragmentation theory. It is unlikely that projection effects can explain this discrepancy. We suggest that the continuous accretion of gas onto the two star-forming filaments, as well as the geometrical bending of the filaments, may account for the observed core spacing.
Conclusions. Our findings suggest that the characteristic fragmentation lengthscale of molecular filaments is quite sensitive to external perturbations from the parent cloud, such as the gravitational accretion of ambient material.

Abstract Copyright: © ESO 2020

Journal keyword(s): stars: formation - ISM: clouds - dust, extinction - ISM: kinematics and dynamics

VizieR on-line data: <Available at CDS (J/A+A/642/A76): list.dat fits/*>

Nomenclature: Fig. A.1, Table A.1: [ZAM2020] NN (Nos 1-57).

Simbad objects: 68

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Number of rows : 68
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME California Molecular Cloud MoC 04 10.0 +39 00           ~ 188 1
2 Barnard 211 DNe 04 17 35 +27 43.1           ~ 141 0
3 LDN 1495 DNe 04 18.1 +27 37           ~ 408 1
4 [ZAM2020] 1 cor 04 19 20.6 +37 28 30           ~ 1 0
5 [ZAM2020] 2 cor 04 19 26.7 +37 21 50           ~ 1 0
6 [ZAM2020] 3 cor 04 19 27.7 +37 28 05           ~ 1 0
7 [ZAM2020] 4 cor 04 19 28.7 +37 20 34           ~ 1 0
8 CMCHerschel 105 cor 04 19 29.821 +37 22 52.29           ~ 2 0
9 [ZAM2020] 6 cor 04 19 36.4 +37 29 05           ~ 1 0
10 [ZAM2020] 7 cor 04 19 36.7 +37 28 46           ~ 1 0
11 CMCHerschel 103 cor 04 19 36.797 +37 26 54.70           ~ 2 0
12 [ZAM2020] 9 cor 04 19 39.8 +37 28 59           ~ 1 0
13 [ZAM2020] 10 cor 04 19 49.5 +37 24 01           ~ 1 0
14 [ZAM2020] 11 cor 04 19 57.5 +37 31 06           ~ 1 0
15 CMCHerschel 101 cor 04 20 03.578 +37 31 23.24           ~ 2 0
16 CMCHerschel 99 cor 04 20 15.031 +37 31 46.81           ~ 2 0
17 [ZAM2020] 14 cor 04 20 26.4 +37 10 25           ~ 1 0
18 [ZAM2020] 15 cor 04 20 30.6 +37 33 31           ~ 1 0
19 [ZAM2020] 16 cor 04 20 33.3 +37 12 09           ~ 1 0
20 [ZAM2020] 17 cor 04 20 34.9 +37 15 38           ~ 1 0
21 CMCHerschel 91 cor 04 20 41.970 +37 33 31.57           ~ 2 0
22 [ZAM2020] 19 cor 04 20 45.5 +37 29 49           ~ 1 0
23 CMCHerschel 102 cor 04 20 47.439 +37 30 47.20           ~ 2 0
24 [ZAM2020] 21 cor 04 20 47.8 +37 17 16           ~ 1 0
25 Barnard 213 DNe 04 20 51 +27 16.3           ~ 249 0
26 CMCHerschel 93 cor 04 20 54.139 +37 33 02.44           ~ 2 0
27 CMCHerschel 96 cor 04 21 00.872 +37 32 41.50           ~ 2 0
28 [ZAM2020] 24 cor 04 21 00.9 +37 31 19           ~ 1 0
29 CMCHerschel 106 cor 04 21 01.029 +37 20 51.54           ~ 3 0
30 [ZAM2020] 26 cor 04 21 02.8 +37 34 24           ~ 1 0
31 [ZAM2020] 27 cor 04 21 05.8 +37 24 12           ~ 1 0
32 CMCHerschel 104 cor 04 21 07.870 +37 25 21.83           ~ 2 0
33 CMCHerschel 85 cor 04 21 14.251 +37 36 39.85           ~ 3 0
34 CMCHerschel 84 cor 04 21 14.621 +37 37 47.72           ~ 3 0
35 [ZAM2020] 31 cor 04 21 15.5 +37 31 49           ~ 1 0
36 CMCHerschel 86 cor 04 21 18.027 +37 35 36.52           ~ 2 0
37 CMCHerschel 90 cor 04 21 18.252 +37 33 50.29           ~ 4 0
38 [ZAM2020] 34 cor 04 21 20.7 +37 34 51           ~ 1 0
39 [ZAM2020] 35 cor 04 21 23.3 +37 32 20           ~ 1 0
40 [ZAM2020] 36 cor 04 21 24.4 +37 36 31           ~ 1 0
41 [ZAM2020] 37 cor 04 21 26.2 +37 36 38           ~ 1 0
42 [ZAM2020] 38 cor 04 21 29.9 +37 33 24           ~ 1 0
43 [ZAM2020] 39 cor 04 21 32.7 +37 42 23           ~ 1 0
44 [ZAM2020] 40 cor 04 21 33.7 +37 32 54           ~ 1 0
45 [ZAM2020] 41 cor 04 21 35.6 +37 36 22           ~ 1 0
46 [ZAM2020] 42 cor 04 21 37.4 +37 37 43           ~ 1 0
47 CMCHerschel 87 cor 04 21 37.524 +37 35 25.80           ~ 2 0
48 CMCHerschel 97 cor 04 21 38.818 +37 32 36.77           ~ 2 0
49 CMCHerschel 88 cor 04 21 38.873 +37 34 26.90           ~ 3 0
50 CMCHerschel 89 cor 04 21 41.241 +37 33 50.40           ~ 3 0
51 [ZAM2020] 47 cor 04 21 41.3 +37 37 16           ~ 1 0
52 CMCHerschel 98 cor 04 21 44.630 +37 32 18.24           ~ 2 0
53 CMCHerschel 92 cor 04 21 45.331 +37 33 22.89           ~ 3 0
54 CMCHerschel 95 cor 04 21 50.662 +37 32 49.60           ~ 2 0
55 [ZAM2020] 51 cor 04 21 51.2 +37 32 03           ~ 1 0
56 CMCHerschel 100 cor 04 21 54.424 +37 31 46.17           ~ 2 0
57 [ZAM2020] 53 cor 04 21 55.2 +37 38 04           ~ 1 0
58 [ZAM2020] 54 cor 04 21 57.7 +37 20 10           ~ 1 0
59 [ZAM2020] 55 cor 04 22 02.8 +37 34 17           ~ 1 0
60 [ZAM2020] 56 cor 04 22 07.4 +37 16 49           ~ 1 0
61 [ZAM2020] 57 cor 04 22 09.7 +37 14 39           ~ 1 0
62 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4971 0
63 NAME Ori A MoC 05 38 -07.1           ~ 3187 0
64 NGC 6334 HII 17 20 53 -36 07.9           ~ 740 0
65 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 1195 1
66 NAME Serpens South Cluster Cl* 18 30 03.00 -02 01 58.2           ~ 148 0
67 NAME Dragon Nebula DNe 18 42 50.6 -04 03 30           ~ 177 0
68 [DLW84] G35.2N HII 18 58 13.036 +01 40 36.00           ~ 138 0

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