2006A&A...456..235M


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.04CEST22:22:27

2006A&A...456..235M - Astronomy and Astrophysics, volume 456, 235-244 (2006/9-2)

Study of photon dominated regions in Cepheus B.

MOOKERJEA B., KRAMER C., ROELLIG M. and MASUR M.

Abstract (from CDS):

The aim of the paper is to understand the emission from the photon dominated regions in Cepheus B, estimate the column densities of neutral carbon in bulk of the gas in Cepheus B and to derive constraints on the factors which determine the abundance of neutral carbon relative to CO. This paper presents 15'x15' fully sampled maps of [CI] at 492 GHz and 12CO 4-3 observed with KOSMA at 1' resolution. The new observations have been combined with the FCRAO 12CO 1-0, IRAM-30m 13CO 2-1 and C18O 1-0 data, and far-infrared continuum data from HIRES/IRAS. The KOSMA-τ spherical PDR model has been used to understand the [CI] and CO emission from the PDRs in Cepheus B and to explain the observed variation of the relative abundances of both C0 and CO. The emission from the PDR associated with Cepheus B is primarily at VLSR between -14 and -11km/s. We estimate about 23% of the observed [CII] emission from the molecular hotspot is due to the ionized gas in the HII region. Over bulk of the material the C0 column density does not change significantly, (2.0±1.4)x1017cm–2, although the CO column density changes by an order of magnitude. The observed C/CO abundance ratio varies between 0.06 and 4 in Cepheus B. We find an anti-correlation of the observed C/CO abundance ratio with the observed hydrogen column density, which holds even when all previous observations providing C/CO ratios are included. Here we show that this observed variation of C/CO abundance with total column density can be explained only by clumpy PDRs consisting of an ensemble of clumps. At high H2 column densities high mass clumps, which exhibit low C/CO abundance, dominate, while at low column densities, low mass clumps with high C/CO abundance dominate.

Abstract Copyright:

Journal keyword(s): ISM: clouds - ISM: dust, extinction - ISM: H II regions - ISM: structure

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Polaris Cirrus Cloud MoC 01 52 29.6 +87 40 31           ~ 71 0
2 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 965 3
3 NGC 1333 OpC 03 29 11 +31 18.6           ~ 1221 1
4 M 42 HII 05 35 17.3 -05 23 28           ~ 3730 0
5 NAME Ori A MoC 05 38 -07.1           ~ 2677 0
6 NGC 2024 Cl* 05 41 43 -01 50.5           ~ 1072 1
7 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3035 0
8 SH 2-106 HII 20 27 26.8 +37 22 49           ~ 410 2
9 18P 59 HII 20 32 31.2 +40 16 35           ~ 63 0
10 NGC 7023 RNe 21 01 36.9 +68 09 48           ~ 631 0
11 SH 2-140 OpC 22 19 07.8 +63 17 07           ~ 634 2
12 IRAS 22176+6303 Y*O 22 19 17.978 +63 18 52.92           ~ 590 0
13 NAME Cepheus A SFR 22 56 17.9 +62 01 49           ~ 698 2
14 HD 217061 Be* 22 56 42.5498828504 +62 37 29.572040833 9.22 9.37 8.9     B5 93 0
15 HD 217086 Y*O 22 56 47.1887219290 +62 43 37.654789076 7.88 8.30 7.66 8.35   O7Vnn((f))z 243 0
16 2MASS J22570220+6238251 Y*O 22 57 02.20 +62 38 25.2     20.32   17.62 ~ 8 0
17 LBN 110.11+02.44 HII 22 57 06 +62 38.2           ~ 100 0
18 2MASS J22570622+6237555 Y*O 22 57 06.2221389822 +62 37 55.541690491 23.249   21.47   17.86 ~ 7 0
19 NAME Cep B cor 22 57 07.00 +62 37 22.3           ~ 79 0
20 NAME III CEP ASSOC As* 23 04.2 +63 24           ~ 295 0

    Equat.    Gal    SGal    Ecl

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2020.08.04-22:22:27

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