2010ApJ...718..666F


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.22CET21:46:25

2010ApJ...718..666F - Astrophys. J., 718, 666-682 (2010/August-1)

The initial conditions of clustered star formation. III. The deuterium fractionation of the Ophiuchus B2 core.

FRIESEN R.K., DI FRANCESCO J., MYERS P.C., BELLOCHE A., SHIRLEY Y.L., BOURKE T.L. and ANDRE P.

Abstract (from CDS):

We present N2D+ 3-2 (IRAM), and H2D+ 111-110 and N2H+ 4-3 (JCMT) maps of the small cluster-forming Ophiuchus B2 core in the nearby Ophiuchus molecular cloud. In conjunction with previously published N2H+ 1-0 observations, the N2D+ data reveal the deuterium fractionation in the high-density gas across Oph B2. The average deuterium fractionation RD = N(N2D+)/N(N2H+) ∼ 0.03 over Oph B2, with several small scale RD peaks and a maximum RD= 0.1. The mean RD is consistent with previous results in isolated starless and protostellar cores. The column density distributions of both H2D+ and N2D+ show no correlation with total H2column density. We find, however, an anticorrelation in deuterium fractionation with proximity to the embedded protostars in Oph B2 to distances ≳0.04 pc. Destruction mechanisms for deuterated molecules require gas temperatures greater than those previously determined through NH3 observations of Oph B2 to proceed. We present temperatures calculated for the dense core gas through the equating of non-thermal line widths for molecules (i.e., N2D+ and H2D+) expected to trace the same core regions, but the observed complex line structures in B2 preclude finding a reasonable result in many locations. This method may, however, work well in isolated cores with less complicated velocity structures. Finally, we use RD and the H2D+ column density across Oph B2 to set a lower limit on the ionization fraction across the core, finding a mean xe,lim≳ fewx10–8. Our results show that care must be taken when using deuterated species as a probe of the physical conditions of dense gas in star-forming regions.

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Journal keyword(s): ISM: kinematics and dynamics - ISM: molecules - ISM: structure - radio lines: ISM - stars: formation

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 - 2021
#notes
1 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 616 1
2 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 468 0
3 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 563 0
4 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 709 0
5 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 435 1
6 NGC 1985 RNe 05 37 47.8 +31 59 24           ~ 130 2
7 NAME Ori B9 Cloud Cld 05 42 30.5 -01 20 33           ~ 17 0
8 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 695 1
9 NAME rho Oph C Cloud MoC 16 26 53.1 -24 32 31           ~ 57 0
10 NAME rho Oph Cloud B1 PoC 16 27 10.5 -24 29 30           ~ 51 1
11 NAME rho Oph B Cloud MoC 16 27 11 -24 28.5           ~ 67 1
12 [JJK2008] SMM J162725-24273 smm 16 27 25.10 -24 27 28.4           ~ 3 0
13 NAME rho Oph B2 Cloud PoC 16 27 27.9 -24 26 29           ~ 75 1
14 [SSG2006] MMS016 cor 16 27 28.1 -24 27 11           ~ 22 0
15 Elia 2-32 Y*O 16 27 28.44576 -24 27 21.0348           K6.5 106 1
16 Elia 2-33 Y*O 16 27 30.18024 -24 27 43.3656           M2 111 1
17 [FDS2010] B2-N6 cor 16 27 32.30 -24 27 00.0           ~ 2 0
18 [FDS2009] B2-A7 cor 16 27 32.50 -24 26 57.0           ~ 4 0
19 NAME rho Oph F MoC 16 27 37.3 -24 42 28           ~ 58 0
20 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3114 1

    Equat.    Gal    SGal    Ecl

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