1998ApJ...500..280F

Query : 1998ApJ...500..280F

1998ApJ...500..280F - Astrophys. J., 500, 280-290 (1998/June-2)

Infrared spectroscopy of ultracompact H II regions.

FAISON M., CHURCHWELL E., HOFNER P., HACKWELL J., LYNCH D.K. and RUSSELL R.W.

Abstract (from CDS):

We present intermediate-resolution (λ/Δλ ~ 60) spectra of 21 ultracompact H II regions in the spectral range from 3 to 13 µm. The 9.7 µm silicate feature is seen in absorption, and the 12.8 µm [Ne II] fine structure line is seen in emission toward most of the observed nebulae. The strengths of both features vary enormously from nebula to nebula, suggesting large variations in the column densities of both Ne II and silicates toward these objects. Near-IR features attributed to polycyclic aromatic hydrocarbons (PAHs) are detected in six of the sources.

Spherically symmetric dust shell models were calculated to obtain the best fits to those nebulae for which distances are known, and spectral energy distributions are available in the range of 1 mm to 1 µm. The models are used to infer properties of the dust cocoon such as the distribution of density and temperature with radius, shell thickness, outer shell radius, and dust abundances. Our results are consistent with previous models that predict large dust cocoons with central cavities, sharp temperature gradients, and approximately constant density in the outer regions.

Abstract Copyright: ∼

Journal keyword(s): Stars: Circumstellar Matter - ISM: Dust, Extinction - ISM: H II Regions - Infrared: ISM: Lines and Bands - ISM: Abundances

CDS comments: Table 1 : IRAS 18006+2422 and 18174+1612 misprint for 18006-2422 and 18174-1612

Simbad objects: 35

Full paper

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Number of rows : 35

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag B	Mag V	Sp type	#ref 1850 - 2026	#notes
1	RAFGL 2046	HII	18 00 32.1	-24 04 03			~	380	0
2	GAL 005.97-01.17	HII	18 03 40.51	-24 22 44.4			~	33	0
3	IRAS 18006-2422	HII	18 03 45.7	-24 22 41			~	23	0
4	IRAS 18174-1612	HII	18 20 24.6	-16 11 40			~	32	0
5	GAL 015.04-00.68	HII	18 20 24.81	-16 11 35.0			~	20	1
6	[KCW94] 018.146-00.284	Rad	18 25 01.083	-13 15 39.33			~	4	0
7	IRAS 18222-1317	HII	18 25 02.3	-13 15 51			~	17	0
8	IRAS 18228-1312	HII	18 25 42.2	-13 10 20			~	43	1
9	[KCW94] 018.302-00.391	Rad	18 25 42.366	-13 10 21.85			~	3	0
10	OH 019.61-00.23	Mas	18 27 37.8	-11 56 27			~	24	0
11	GAL 019.61-00.23	HII	18 27 38.0	-11 56 42			~	162	0
12	GAL 019.60-00.23	HII	18 27 38.11	-11 56 39.5			~	16	0
13	[CKW87] 184135.6-042104	HII	18 44 14.3	-04 17 57			~	10	0
14	GRS G028.29 -00.37	HII	18 44 18.6	-04 17 53			~	37	0
15	CORNISH G029.9559-00.0168	Y*O	18 46 04.18	-02 39 21.3			~	385	0
16	GAL 032.80+00.19	HII	18 50 30	-00 02.0			~	38	0
17	RAFGL 2271	SFR	18 53 18.54	+01 14 57.9			~	537	0
18	[WC89] 035.20-1.74	HII	19 01 46.4	+01 13 25			~	12	0
19	GAL 035.20-01.74	Y*O	19 01 46.49	+01 13 24.7			~	78	1
20	CORNISH G037.8731-00.3996	HII	19 01 53.58	+04 12 51.7			~	42	1
21	IRAS 19110+1045	Y*O	19 13 22.0427	+10 50 53.336			~	132	0
22	Caswell OH 045.12+00.13	HII	19 13 27.85	+10 53 36.7			~	121	0
23	[WBN74] W 51 IRS 2	SFR	19 23 39.93	+14 31 09.4			~	321	0
24	NAME W 51 North	Rad	19 23 40.0	+14 30 51			~	169	0
25	SH 2-88 B	HII	19 46 48.2	+25 12 21			~	159	2
26	W 58a	HII	20 01 45.8	+33 32 43			~	294	4
27	GAL 078.4+02.6	HII	20 19 39.22	+40 56 36.6			~	14	0
28	IRAS 20178+4046	HII	20 19 39.3	+40 56 30			~	48	1
29	V* BC Cyg	s*r	20 21 38.5478957040	+37 31 58.925226936	14.61	11.30	M3.5Ia	171	0
30	GAL 075.78+00.34	cor	20 21 44.00	+37 26 38.0			~	131	1
31	WSRTGP 2025+3712	HII	20 27 26.4	+37 22 48			~	48	0
32	NAME SH 2-106 IR	Y*O	20 27 26.502	+37 22 42.03			~	168	1
33	[KCW94] 076.383-00.621	HII	20 27 26.767	+37 22 47.96			~	9	0
34	SH 2-140	OpC	22 19 07.8	+63 17 07			~	668	2
35	IRAS 22176+6303	Y*O	22 19 18.23	+63 18 47.5			~	600	0

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