The distribution of ND2H in LDN1689N

Abstract

Finding tracers of the innermost regions of prestellar cores is important for understanding their chemical and dynamical evolution before the onset of gravitational collapse. While classical molecular tracers, such as CO and CS, have been shown to be strongly depleted in cold, dense gas by condensation on grain mantles, it has been a subject of discussion to what extent nitrogen-bearing species, such as ammonia, are affected by this process. As deuterium fractionation is efficient in cold, dense gas, deuterated species are excellent tracers of prestellar cores. A comparison of the spatial distribution of neutral and ionized deuterated species with the dust continuum emission can thus provide important insights into the physical and chemical structure of such regions. We study the spatial distribution of the ground-state 335.5 GHz line of ND2H in LDN1689N, using APEX, and compare it with the distribution of the DCO+(3--2) line, as well as the 350 micron dust continuum emission observed with the SHARC~II bolometer camera at CSO. While the distribution of the ND2H emission in LDN1689N is generally similar to that of the 350 microns dust continuum emission, the peak of the ND2H emission is offset by ~10'' to the East from the dust continuum and DCO+ emission peak. ND2H and ND3 share the same spatial distribution. The observed offset between the ND2H and DCO+ emission is consistent with the hypothesis that the deuterium peak in LDN1689N is an interaction region between the outflow shock from IRAS16293--2422 and the dense ambient gas. We detect the J = 4 - 3 line of H13CO+ at 346.998 GHz in the image side band serendipitously. This line shows the same spatial distribution as DCO+(3--2), and peaks close to the 350 mic emission maximum which provides further support for the shock interaction scenario.

4 pages Accepted by Astronomy and Astrophysics, special APEX edition

Cited by in corpus (17)

• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Detection of 15NH2D in dense cores: A new tool for measuring the 14N/15N ratio in the cold ISM
• Spin-state chemistry of deuterated ammonia
• CH2D+, the Search for the Holy Grail
• Deuteration of ammonia in the starless core Ophiuchus/H-MM1
• DNC/HNC and N2D+/N2H+ ratios in high-mass star forming cores
• Deuteration around the ultracompact HII region Mon R2
• Collisional excitation of doubly and triply deuterated ammonia ND${}_2$H and ND${}_3$ by H${}_2$
• Stratified NH and ND emission in the prestellar core 16293E in L1689N
• Star Formation and Feedback: A Molecular Outflow-Prestellar Core Interaction in L1689N
• Collisional excitation of doubly deuterated ammonia NHD2 by para-H2
• The effect of multilayer ice chemistry on gas-phase deuteration in starless cores
• The molecular environment of the solar-type protostar IRAS 16293-2422
• Far-Infrared detection of H2D+ toward Sgr B2
• Sensitivity of microwave spectra of deuterated ammonia to variation of electron-to-proton mass ratio
• Nascent chemical complexity in prestellar core IRAS 16293E: complex organics and deuterated methanol