2009A&A...499..799L


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.08CEST20:31:26

2009A&A...499..799L - Astronomy and Astrophysics, volume 499, 799-809 (2009/6-1)

Oxygen in dense interstellar gas. The oxygen abundance of the star forming core ρ Ophiuchi A.

LISEAU R. and JUSTTANONT K.

Abstract (from CDS):

Oxygen is the third most abundant element in the universe, but its chemistry in the interstellar medium is still not understood well. To critically examine the entire oxygen budget, we initially attempt to estimate the abundance of atomic oxygen, O, in the only region where molecular oxygen, O2, has been detected to date. We analysed ISOCAM-CVF spectral image data toward ρ Oph A to derive the temperatures and column densities of H2 at the locations of ISO-LWS observations of two [OI] 3PJ lines. The intensity ratios of the (J=1-2) 63µm to (J=0-1) 145µm lines largely exceed ten, attesting to these lines being optically thin. This is confirmed by radiative transfer calculations, making these lines suitable for abundance determinations. For that purpose, we calculated line strengths and compared them to the LWS observations. Excess [OI] emission is observed to be associated with the molecular outflow from VLA1623. For this region, we determine the physical parameters, T and N(H2), from the CAM observations, and the gas density, n(H2), is determined from the flux ratio of the [OI]63µm and [OI]145µm lines. For the oxygen abundance, our analysis essentially leads to three possibilities: (1) extended low-density gas with standard ISM O-abundance, (2) compact high-density gas with standard ISM O-abundance, and (3) extended high-density gas with reduced oxygen abundance, [O/H]∼2x10–5. As option (1) disregards valid [OI]145µm data, we do not find it very compelling; instead, we favour option (3), as lower abundances are expected as a result of chemical cloud evolution, but we are not able to dismiss option (2) entirely. Observations at higher angular resolution than offered by the LWS are required to decide between these possibilities.

Abstract Copyright:

Journal keyword(s): ISM: abundances - ISM: molecules - ISM: dust, extinction - ISM: clouds - ISM: individual objects: rho Ophiuchi A - ISM: individual objects: VLA1623

Simbad objects: 13

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Number of rows : 13

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 HD 147889 pr* 16 25 24.3162969787 -24 27 56.570239619 8.56 8.73 7.90     B2III/IV 434 1
2 EM* SR 4 Or* 16 25 56.1659484606 -24 20 48.239269835     12.80 11.7 10.7 K0:Ve 152 1
3 Haro 1-6 Or* 16 26 03.0281201323 -24 23 36.193999164   14.15 14.01 12.38 10.80 K0 204 1
4 Elia 2-20 TT* 16 26 18.8782824640 -24 28 19.698059817           ~ 93 1
5 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 200 1
6 GSS 32 TT* 16 26 24.0521249616 -24 24 48.105099750       17.81 15.58 K5-K6 95 1
7 NAME rho Oph A Cloud MoC 16 26 26.4 -24 22 33           ~ 239 1
8 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 374 0
9 [SSG2006] MMS002 smm 16 26 26.50 -24 24 30.9           ~ 241 0
10 NAME rho Oph A SM 1N cor 16 26 27.12 -24 23 34.8           ~ 43 0
11 GSS 35 TT* 16 26 34.1750440278 -24 23 28.331873112     16.53 14.75 12.51 B3 215 1
12 GSS 39 Y*O 16 26 45.0321556934 -24 23 07.808781522           M0 142 1
13 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3037 0

    Equat.    Gal    SGal    Ecl

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2020.08.08-20:31:26

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