1999MNRAS.303..367S


Query : 1999MNRAS.303..367S

1999MNRAS.303..367S - Mon. Not. R. Astron. Soc., 303, 367-379 (1999/February-3)

Mid-infrared imaging and spectroscopy of the southern H II region RCW 38.

SMITH C.H., BOURKE T.L., WRIGHT C.M., SPOON H.W.W., AITKEN D.K., ROBINSON G., STOREY J.W.V., FUJIYOSHI T., ROCHE P.F. and LEHMANN T.

Abstract (from CDS):

We present mid-infrared images and an 8–13 µ m spectrum of the southern HII region RCW 38. We determine the dust colour temperature from both our spectrum and images at 10 and 20 µ m, and deduce the gas excitation from an image in the [SIV] fine-structure line, as well as spectra of the [ArIII], [SIV] and [NeII] fine-structure lines. Our observations are consistent with a complex of sources associated with the RCW 38 IRS1 region, which represent knots of material in a shell, or ridge, surrounding a cavity of about 0.1 pc in radius, which is itself created by the stellar wind of the hot young source IRS2. The dust temperature does not peak closest to IRS2, but rather along the centre of the ridge, and is remarkably uniform over the extent of our image. From photoionization models for the observed line ratios at IRS1 we deduce a stellar effective temperature and gas density of about 43 000–48 000 K and 104 cm–3 respectively. Whilst the star, or star cluster, IRS2 is ultimately responsible for the observed thermal and ionic emission, the relatively uniform dust temperature implies that the bulk of the dust heating in the region is provided by resonantly trapped Lyman α photons, rather than direct stellar photons. This then also implies that the dust is depleted with respect to the gas by a factor of at least 100 from its normal interstellar value. The small-scale spatial variations in the continuum emission and temperature can be explained by changes in the density and/or gas-to-dust mass ratio.

Abstract Copyright: 1999 RAS

Journal keyword(s): stars: formation - HII regions - infrared: ISM: continuum

Nomenclature: Fig.1: [SBW99] A (Nos A-D).

Simbad objects: 16

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Number of rows : 16
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME W3 IRS 5 Y*O 02 25 40.54 +62 05 51.4           B1 343 0
2 IC 1795 HII 02 25 43.5 +62 06 13           ~ 236 0
3 NAME Ori Trapezium OpC 05 35 16.5 -05 23 14           ~ 1568 1
4 RCW 38 SFR 08 59 05.50 -47 30 39.4           ~ 297 2
5 [FP74] RCW 38 IRS 2 Y*O 08 59 05.6555109888 -47 30 40.941723780       14.05 11.20 O5.5V 24 1
6 NGC 3603 OpC 11 15 11 -61 15.5           ~ 1032 1
7 [GS70] 298.2-00.3 HII 12 10 01.886 -62 50 00.46           ~ 66 1
8 GAL 333.6-00.2 HII 16 22 11 -50 05.6           ~ 144 0
9 GAL 029.9-00.0 HII 18 46 08.0 -02 40 41           ~ 34 0
10 GAL 045.1+00.1 HII 19 13.4 +10 51           ~ 13 0
11 GAL 045.13+00.14 HII 19 13 28.3 +10 53 41           ~ 23 1
12 W 58a HII 20 01 45.8 +33 32 43           ~ 283 4
13 [FP74] RCW 38 IRS 3 IR ~ ~           ~ 1 0
14 [FP74] RCW 38 IRS 1 IR ~ ~           ~ 12 0
15 RCW 38E MoC ~ ~           ~ 2 0
16 RCW 38W MoC ~ ~           ~ 2 0

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2023.01.27-14:40:42

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