2012A&A...547A..33V


Query : 2012A&A...547A..33V

2012A&A...547A..33V - Astronomy and Astrophysics, volume 547A, 33-33 (2012/11-1)

Upper limit for the D2H+ ortho-to-para ratio in the prestellar core 16293E (CHESS).

VASTEL C., CASELLI P., CECCARELLI C., BACMANN A., LIS D.C., CAUX E., CODELLA C., BECKWITH J.A. and RIDLEY T.

Abstract (from CDS):

The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large abundances of H2D+ and D2H+, which are very useful probes of the early stages of star and planet formation. The ground-state rotational ortho-D2H+ 11,1-00,0 transition at 1476.6 GHz in the prestellar core 16293E has been searched for with the Herschel HIFI instrument, within the CHESS (Chemical HErschel Surveys of Star forming regions) Key Program. The line has not been detected at the 21 mK km/s level (3σ integrated line intensity). We used the ortho-H2D+ 11,0-11,1 transition and para-D2H+ 11,0-10,1 transition detected in this source to determine an upper limit on the ortho-to-para D2H+ ratio as well as the para-D2H+/ortho-H2D+ ratio from a non-local thermodynamic equilibrium analysis. The comparison between our chemical modeling and the observations suggests that the CO depletion must be high (larger than 100), with a density between 5x105 and 106cm–3. Also the upper limit on the ortho-D2H+ line is consistent with a low gas temperature (∼11K) with a ortho-to-para ratio of 6 to 9, i.e. 2 to 3 times higher than the value estimated from the chemical modeling, making it impossible to detect this high frequency transition with the present state of the art receivers.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: individual objects: 16293E - ISM: abundances - line: identification - radiative transfer

VizieR on-line data: <Available at CDS (J/A+A/547/A33): kida.dat>

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NAME rho Oph E MoC 16 27 02.0 -24 38 31           ~ 62 0
2 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3375 1
3 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1172 1
4 NAME IRAS 16293-2422B Y*O 16 32 22.63 -24 28 31.8           ~ 237 0
5 NAME IRAS 16293-2422A Y*O 16 32 22.869 -24 28 36.11           ~ 145 0
6 LDN 1689N DNe 16 32 25.96 -24 28 46.2           ~ 114 0
7 NAME IRAS 16293E cor 16 32 29.060 -24 29 10.27           ~ 56 1

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2022.08.15-15:08:24

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