2019ApJ...877...93C

Query : 2019ApJ...877...93C

2019ApJ...877...93C - Astrophys. J., 877, 93-93 (2019/June-1)

Droplets. I. Pressure-dominated coherent structures in L1688 and B18.

CHEN H.H.-H., PINEDA J.E., GOODMAN A.A., BURKERT A., OFFNER S.S.R., FRIESEN R.K., MYERS P.C., ALVES F., ARCE H.G., CASELLI P., CHACON-TANARRO A., CHEN M.C.-Y., DI FRANCESCO J., GINSBURG A., KEOWN J., KIRK H., MARTIN P.G., MATZNER C., PUNANOVA A., REDAELLI E., ROSOLOWSKY E., SCIBELLI S., SEO Y., SHIRLEY Y., SINGH A. (The GAS Collaboration)

Abstract (from CDS):

We present the observation and analysis of newly discovered coherent structures in the L1688 region of Ophiuchus and the B18 region of Taurus. Using data from the Green Bank Ammonia Survey, we identify regions of high density and near-constant, almost-thermal velocity dispersion. We reveal 18 coherent structures are revealed, 12 in L1688 and 6 in B18, each of which shows a sharp "transition to coherence" in velocity dispersion around its periphery. The identification of these structures provides a chance to statistically study the coherent structures in molecular clouds. The identified coherent structures have a typical radius of 0.04 pc and a typical mass of 0.4 M☉, generally smaller than previously known coherent cores identified by Goodman et al., Caselli et al., and Pineda et al. We call these structures "droplets." We find that, unlike previously known coherent cores, these structures are not virially bound by self-gravity and are instead predominantly confined by ambient pressure. The droplets have density profiles shallower than a critical Bonnor-Ebert sphere, and they have a velocity (VLSR) distribution consistent with the dense gas motions traced by NH3 emission. These results point to a potential formation mechanism through pressure compression and turbulent processes in the dense gas. We present a comparison with a magnetohydrodynamic simulation of a star-forming region, and we speculate on the relationship of droplets with larger, gravitationally bound coherent cores, as well as on the role that droplets and other coherent structures play in the star formation process.

Abstract Copyright: © 2019. The American Astronomical Society.

Journal keyword(s): ISM: clouds - ISM: individual objects: L1688, B18 - ISM: kinematics and dynamics - magnetohydrodynamics MHD - radio lines: ISM - stars: formation

Nomenclature: Figs 1-6, Table 1: [CPG2019] L1688-aNW (Nos d1-d12, c1E-c1W, c2-c5), [CPG2019] B18-dN (Nos d1-d6).

Simbad objects: 186

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Number of rows : 186
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 [LMG94] Per 3 PoC 03 28 42.8 +31 05 40           ~ 6 0
2 NGC 1333 OpC 03 29 09.2 +31 20 59           ~ 1575 1
3 [LMG94] Per 6 PoC 03 30 14.9 +30 22 48           ~ 13 0
4 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1553 0
5 LDN 1471 DNe 03 48.0 +32 54           ~ 349 0
6 LDN 1489 DNe 04 04 47.5 +26 19 42           ~ 238 0
7 LDN 1400K DNe 04 10 48.6 +54 53 14           ~ 32 0
8 LDN 1498 DNe 04 11.0 +24 58           ~ 306 0
9 LDN 1495 DNe 04 18.1 +27 37           ~ 408 1
10 LDN 1400G DNe 04 25 10.5 +54 19 11           ~ 22 0
11 [CPG2019] B18-d1 cor 04 26 58.95 +24 41 16.6           ~ 1 0
12 Barnard 217 DNe 04 27 46.5 +26 17 52           ~ 89 0
13 LDN 1524 DNe 04 27 57.7 +24 39 18           ~ 87 0
14 Barnard 218 DNe 04 28.1 +26 16           ~ 43 0
15 [CPG2019] B18-d2 cor 04 29 24.13 +24 34 42.2           ~ 2 0
16 [OMK2002] 29 MoC 04 30 00.4 +24 25 53           ~ 2 0
17 [LM99] L1524-4 cor 04 30 05.7 +24 25 16           ~ 12 0
18 [CPG2019] B18-d3 cor 04 30 05.71 +24 25 40.6           ~ 2 0
19 [KBB2008] L1524-4 C1 cor 04 30 07.90 +24 25 44.5           ~ 2 0
20 [CPG2019] B18-d4 cor 04 31 54.48 +24 32 28.2           ~ 2 0
21 [KBB2008] B18-1 C1 cor 04 31 55.40 +24 32 33.7           ~ 2 0
22 [OMK2002] 31 MoC 04 31 55.7 +24 32 09           ~ 3 0
23 JCMTSF J043155.5+243254 PoC 04 31 55.9 +24 32 49           ~ 42 0
24 [LM99] B18-1 cor 04 31 57.7 +24 32 30           ~ 4 0
25 [OMK2002] 33b MoC 04 32 43.8 +24 24 06           ~ 3 0
26 NAME Kutner's Cloud MoC 04 32 44.6 +24 23 13           ~ 283 0
27 [KBB2008] TMC-2 C1 cor 04 32 45.90 +24 24 08.0           ~ 2 0
28 [CPG2019] B18-d5 cor 04 32 46.54 +24 24 51.9           ~ 1 0
29 [WMD94] Tau E 2 Cld 04 32 48.2 +24 23 33           ~ 2 0
30 [LM99] TMC 2 cor 04 32 48.7 +24 24 12           ~ 4 0
31 TMC-3A PoC 04 35 33.7 +24 08 47           ~ 4 0
32 [LM99] 45 cor 04 35 35.5 +24 08 55           ~ 10 1
33 [OMK2002] 35 MoC 04 35 36.3 +24 09 04           ~ 2 0
34 [CPG2019] B18-d6 cor 04 35 36.32 +24 09 00.7           ~ 2 0
35 [KBB2008] B18-4 C1 cor 04 35 36.70 +24 09 05.0           ~ 2 0
36 NAME B18-I DNe 04 35 39 +24 09.1           ~ 8 0
37 TMC-3B PoC 04 35 39.6 +24 10 07           ~ 3 0
38 IRAS 04365+2535 Y*O 04 39 35.19360 +25 41 44.7252           ~ 330 0
39 LDN 1527 DNe 04 39 53 +25 45.0           ~ 689 0
40 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4971 0
41 Barnard 220 DNe 04 41 38.8 +26 00 42           ~ 141 0
42 LDN 1534 DNe 04 41 46 +25 41.4           ~ 45 0
43 NAME [BM89] L1517B cor 04 55 18.8 +30 38 04           ~ 163 0
44 NAME [BM89] L1582A DNe 05 31 18.4 +12 30 31           ~ 33 0
45 NAME lam Ori Cloud Cld 05 35 06 +09 56.0           ~ 76 0
46 NAME Ori A MoC 05 38 -07.1           ~ 3187 0
47 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1498 0
48 JCMTSF J054429.8+090856 DNe 05 44 30 +09 08.8           ~ 22 0
49 LDN 134A DNe 15 53 36.4 -04 35 26           ~ 49 0
50 NAME Upper Sco Association As* 16 12 -23.4           ~ 1586 1
51 [CPG2019] L1688-c1W cor 16 26 45.22 -24 33 30.5           ~ 2 0
52 [MNN2010] 18 cor 16 26 45.3 -24 33 27           ~ 2 0
53 [CPG2019] L1688-d1 cor 16 26 47.07 -24 33 08.3           ~ 2 0
54 [MAN98] C-MM9 mm 16 26 48.100 -24 32 12.50           ~ 3 0
55 [SSG2006] MMS055 mm 16 26 48.2 -24 33 01           ~ 2 0
56 [CPG2019] L1688-c1E cor 16 26 49.36 -24 32 39.0           ~ 2 0
57 NAME rho Oph C-W PoC 16 26 50.0 -24 32 49           ~ 5 0
58 [MNN2010] 24 cor 16 26 52.9 -24 37 12           ~ 2 0
59 [MNN2010] 23 cor 16 26 52.9 -24 36 52           ~ 2 0
60 [SSG2006] MMS059 mm 16 26 52.9 -24 34 45           ~ 2 0
61 NAME rho Oph C Cloud MoC 16 26 53.1 -24 32 31           ~ 80 0
62 [MAN98] C-MM1 mm 16 26 53.7 -24 35 11           ~ 3 0
63 [CPG2019] L1688-d2 cor 16 26 54.54 -24 36 52.4           ~ 1 0
64 [SSG2006] MMS068 mm 16 26 55.1 -24 38 10           ~ 2 0
65 [MNN2010] 25 cor 16 26 55.9 -24 36 31           ~ 2 0
66 [CPG2019] L1688-c2 cor 16 26 56.89 -24 30 18.7           ~ 2 0
67 [CPG2019] L1688-d3 cor 16 26 57.07 -24 31 44.8           ~ 1 0
68 NAME rho Oph C-N PoC 16 26 57.2 -24 31 39           ~ 12 0
69 [MNN2010] 27 cor 16 26 57.3 -24 31 23           ~ 2 0
70 [MNN2010] 28 cor 16 26 57.4 -24 37 53           ~ 2 0
71 [MAN98] E-MM1 mm 16 26 57.7 -24 36 56           ~ 4 0
72 [MAN98] C-MM2 mm 16 26 58.4 -24 33 53           ~ 5 0
73 [SSG2006] MMS022 mm 16 26 58.6 -24 34 06           ~ 2 0
74 [FDS2009] C-HC5N cor 16 26 58.8 -24 34 30           ~ 2 0
75 [FDS2009] C-A1 cor 16 26 59.00 -24 34 14.8           ~ 3 0
76 [FDS2009] C-A2 cor 16 26 59.10 -24 32 54.8           ~ 2 0
77 [SSG2006] MMS044 mm 16 26 59.1 -24 31 26           ~ 2 0
78 [CPG2019] L1688-c3 cor 16 26 59.22 -24 33 05.9           ~ 3 0
79 [MAN98] C-MM4 mm 16 26 59.4 -24 34 02           ~ 4 0
80 [CPG2019] L1688-d4 cor 16 26 59.59 -24 34 28.8           ~ 2 0
81 HGBS J162658.9-243422 cor 16 26 59.60 -24 34 25.3           ~ 22 0
82 [FDS2009] C-C2S cor 16 26 59.8 -24 34 13           ~ 2 0
83 [MAN98] C-MM12 mm 16 26 59.800 -24 33 08.75           ~ 3 0
84 [MAN98] C-MM5 mm 16 27 00.1 -24 34 27           ~ 6 0
85 [FDS2009] C-A3 cor 16 27 01.20 -24 34 34.8           ~ 2 0
86 [MAN98] C-MM6 mm 16 27 01.6 -24 34 37           ~ 9 0
87 [MNN2010] 29 cor 16 27 01.9 -24 34 48           ~ 2 0
88 NAME rho Oph E MoC 16 27 02.0 -24 38 31           ~ 65 0
89 [SSG2006] MMS039 mm 16 27 02.0 -24 34 46           ~ 2 0
90 [MAN98] E-MM2b mm 16 27 02.1 -24 38 52           ~ 6 0
91 [MAN98] C-MM10 mm 16 27 02.260 -24 31 42.56           ~ 3 0
92 [MAN98] C-MM7 mm 16 27 03.3 -24 34 22           ~ 4 0
93 [MNN2010] 31 cor 16 27 03.5 -24 38 55           ~ 2 0
94 [MAN98] E-MM2c mm 16 27 03.6 -24 39 26           ~ 4 0
95 [MAN98] E-MM8 mm 16 27 04.190 -24 39 02.59           ~ 3 0
96 [CPG2019] L1688-d5 cor 16 27 04.96 -24 39 17.6           ~ 3 0
97 WL 17 Y*O 16 27 06.77616 -24 38 14.9964           ~ 113 0
98 [MNN2010] 34 cor 16 27 09.6 -24 39 35           ~ 2 0
99 NAME rho Oph B3 Cloud MoC 16 27 20 -24 24.5           ~ 10 1
100 [SSG2006] MMS108 mm 16 27 20.6 -24 24 03           ~ 3 0
101 [MNN2010] 42 cor 16 27 21.1 -24 23 48           ~ 2 0
102 [FDS2009] B3-A1 cor 16 27 21.80 -24 24 42.9           ~ 2 0
103 [MAN98] F-MM1 cor 16 27 21.90 -24 39 52.0           ~ 13 0
104 [FDS2010] B3-N1 cor 16 27 22.00 -24 24 54.7           ~ 2 0
105 [CPG2019] L1688-c4 cor 16 27 22.28 -24 24 52.2           ~ 2 0
106 [MAN98] F-MM2a mm 16 27 23.860 -24 40 35.18           ~ 3 0
107 [FDS2009] F-A2 cor 16 27 24.20 -24 40 52.1           ~ 2 0
108 CRBR 2422.8-3423 Y*O 16 27 24.61320 -24 41 03.4080           ~ 101 1
109 [MNN2010] 46 cor 16 27 24.7 -24 40 57           ~ 2 0
110 NAME rho Oph F1 PoC 16 27 24.9 -24 40 43           ~ 4 0
111 [MAN98] F-MM2 mm 16 27 25.20 -24 40 28.9           ~ 9 0
112 [CPG2019] L1688-d6 cor 16 27 25.50 -24 41 06.2           ~ 2 0
113 [MNN2010] 47 cor 16 27 25.7 -24 24 29           ~ 2 0
114 YLW 15 Y*O 16 27 26.906 -24 40 50.81           ~ 281 1
115 [FDS2009] F-A3 cor 16 27 27.10 -24 40 58.1           ~ 2 0
116 [SSG2006] MMS143 mm 16 27 27.6 -24 24 38           ~ 2 0
117 [MNN2010] 51 cor 16 27 29.2 -24 41 37           ~ 2 0
118 [MNN2010] 52 cor 16 27 30.7 -24 40 36           ~ 2 0
119 LDN 1681B DNe 16 27 35.7 -24 43 26           ~ 27 0
120 [CPG2019] L1688-d7 cor 16 27 37.27 -24 42 50.2           ~ 2 0
121 NAME rho Oph F MoC 16 27 37.3 -24 42 28           ~ 65 0
122 [MNN2010] 57 cor 16 27 38.3 -24 41 16           ~ 2 0
123 [MAN98] F-MM8 mm 16 27 39.220 -24 42 39.77           ~ 2 0
124 [MAN98] F-MM7 mm 16 27 39.810 -24 43 12.25           ~ 4 0
125 [SSG2006] MMS073 mm 16 27 40.2 -24 42 34           ~ 2 0
126 [MAN98] F-MM9 mm 16 27 40.460 -24 42 20.22           ~ 2 0
127 [MNN2010] 58 cor 16 27 42.9 -24 42 38           ~ 2 0
128 [MAN98] F-MM6 mm 16 27 43.730 -24 42 34.59           ~ 2 0
129 [K2003d] rho Oph E1 PoC 16 27 45.5 -24 45 02           ~ 3 0
130 [MNN2010] 59 cor 16 27 46.0 -24 44 42           ~ 2 0
131 [CPG2019] L1688-d8 cor 16 27 46.44 -24 44 45.4           ~ 2 0
132 [SSG2006] MMS081 mm 16 27 48.3 -24 44 44           ~ 2 0
133 [MNN2010] 61 cor 16 27 57.7 -24 35 05           ~ 2 0
134 [YEE2006] 24 cor 16 27 58.30 -24 33 09.7           ~ 4 0
135 [MNN2010] 62 cor 16 27 59.2 -24 34 24           ~ 2 0
136 [CPG2019] L1688-d9 cor 16 27 59.43 -24 33 33.0           ~ 1 0
137 [MNN2010] 63 cor 16 28 00.6 -24 33 01           ~ 2 0
138 [SSG2006] MMS051 mm 16 28 00.6 -24 32 54           ~ 2 0
139 [MNN2010] 64 cor 16 28 03.7 -24 34 44           ~ 2 0
140 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3969 1
141 [MNN2010] 66 cor 16 28 15.8 -24 35 45           ~ 2 0
142 [SSG2006] MMS060 mm 16 28 17.1 -24 36 51           ~ 3 0
143 [MNN2010] 67 cor 16 28 20.4 -24 36 26           ~ 2 0
144 [SSG2006] MMS126 Y*O 16 28 21.61 -24 36 23.4           ~ 38 0
145 [CPG2019] L1688-d10 cor 16 28 22.12 -24 36 16.8           ~ 4 0
146 [MNN2010] 68 cor 16 28 26.4 -24 36 05           ~ 2 0
147 [MAN98] D-MM1 mm 16 28 28.5 -24 19 21           ~ 5 0
148 [L89] R26 PoC 16 28 29.1 -24 18 25           ~ 5 0
149 NAME Ophiuchus D MoC 16 28 29.2 -24 18 25           ~ 122 0
150 [SSG2006] MMS047 mm 16 28 29.4 -24 19 17           ~ 3 0
151 [MAN98] D-MM3 mm 16 28 31.0 -24 17 43           ~ 4 0
152 [CPG2019] L1688-d11 cor 16 28 31.53 -24 18 36.1           ~ 2 0
153 [YEE2006] 27 cor 16 28 32.10 -24 17 43.4           ~ 3 0
154 [MAN98] D-MM4 mm 16 28 32.3 -24 18 01           ~ 5 0
155 [SSG2006] MMS052 mm 16 28 32.7 -24 17 50           ~ 2 0
156 [MAN98] D-MM5 mm 16 28 36.8 -24 18 25           ~ 3 0
157 [MAN98] I-MM1 mm 16 28 57.70 -24 20 33.7           ~ 7 0
158 [SSG2006] MMS041 mm 16 28 58.7 -24 20 49           ~ 2 0
159 LDN 1696B cor 16 28 59.3 -24 20 43           ~ 20 0
160 [CPG2019] L1688-d12 cor 16 28 59.99 -24 20 45.2           ~ 4 0
161 [SSG2006] MMS075 mm 16 29 01.4 -24 21 11           ~ 2 0
162 V* V1003 Oph TT* 16 34 09.1696133088 -15 48 16.776092124     13.44     G5 105 0
163 LDN 43 DNe 16 34 29.3 -15 47 11           ~ 147 1
164 LDN 260 DNe 16 46 58.2 -09 36 20           ~ 43 0
165 LDN 255 DNe 16 47 06.7 -09 35 21           ~ 35 0
166 LDN 158 DNe 16 47 50 -14 05.3           ~ 33 0
167 LDN 234E DNe 16 48 04.5 -10 56 58           ~ 26 0
168 LDN 234A DNe 16 48 06.9 -10 51 48           ~ 23 0
169 LDN 63 DNe 16 50 15.5 -18 06 06           ~ 76 0
170 NAME the Pipe Nebula DNe 17 30 -25.0           ~ 442 1
171 LDN 483 DNe 18 17 35 -04 39.8           ~ 359 0
172 LDN 778 DNe 19 26 32.5 +23 58 42           ~ 51 1
173 LDN 1152 DNe 20 35 50.2 +67 54 22           ~ 73 0
174 NAME [BM89] L1082C DNe 20 51 27.4 +60 19 00           ~ 33 0
175 LDN 1082A DNe 20 53 29.6 +60 14 40           ~ 43 1
176 LDN 1082B DNe 20 53 50.3 +60 09 47           ~ 17 0
177 LDN 1174 DNe 21 00 22.4 +68 12 53           ~ 66 0
178 LDN 1172A DNe 21 02 27.7 +67 54 08           ~ 24 0
179 LDN 970 DNe 21 12 13.1 +47 23 23           ~ 67 0
180 LDN 1031B DNe 21 47 25.7 +47 32 09           ~ 22 0
181 LDN 1251A DNe 22 30 31.8 +75 14 17           ~ 76 2
182 LDN 1251E DNe 22 39 18.3 +75 14 31           ~ 18 0
183 LDN 1262A DNe 23 25 29.6 +74 18 15           ~ 18 0
184 NAME Cepheus Flare MoC 23 34 +72.0           ~ 142 0
185 NAME Gould Belt PoG ~ ~           ~ 956 1
186 LDN 1495SE DNe ~ ~           ~ 3 0

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