The depletion of NO in pre-protostellar cores

Abstract

Understanding the depletion of heavy elements is a fundamental step towards determining the structure of pre-protostellar cores just prior to collapse. We study the dependence of the NO abundance on position in the pre-protostellar cores L1544 and L183. We observed the 150 GHz and 250~GHz transitions of NO and the 93 GHz transitions of \NTHP \ towards L1544 and L183 using the IRAM 30 m telescope. We compare the variation of the NO column density with position in these objects with the H column density derived from dust emission measurements. We find that NO behaves differently from \NTHP \ and appears to be partially depleted in the high density core of L1544. Other oxygen-containing compounds are also likely to be partially depleted in dense-core nuclei. The principal conclusions are that: the prestellar core L1544 is likely to be 'carbon-rich'; the nitrogen chemistry did not reach equilibrium prior to gravitational collapse, and nitrogen is initially (at densities of the order of $10^4$~cm${}^{-3}$) mainly in atomic form; the grain sticking probabilities of atomic C, N and, probably, O are significantly smaller than unity.

References in corpus (3)

• Desorption rates and sticking coefficients for CO and N2 interstellar ices
• The Excitation of N${}_2$H${}^{+}$ in Interstellar Molecular Clouds. I - Models
• The abundances of nitrogen-containing molecules during pre-protostellar collapse

Cited by in corpus (20)

• Chemistry of Dark Clouds: Databases, Networks, and Models
• Dust coagulation and fragmentation in molecular clouds. I. How collisions between dust aggregates alter the dust size distribution
• Interstellar chemistry of nitrogen hydrides in dark clouds
• Nitrogen chemistry and depletion in starless cores
• Elemental nitrogen partitioning in dense interstellar clouds
• Cold N+NH Collisions in a Magnetic Trap
• The gas-phase chemistry of carbon chains in dark cloud chemical models
• CCH in prestellar cores
• Hydrogen cyanide and isocyanide in prestellar cores
• A Search for Hydroxylamine (NH2OH) toward Select Astronomical Sources
• CN in prestellar cores
• New N-bearing species towards OH231.8+4.2: HNCO, HNCS, HC${}_3$N and NO
• A New and Simple Approach to Determine the Abundance of Hydrogen Molecules on Interstellar Ice Mantles
• Nitrogen oxide in protostellar envelopes and shocks: the ASAI survey
• Sulphur-rich cold gas around the hot core precursor G328.2551-0.5321. An APEX unbiased spectral survey of the 2 mm, 1.2 mm, and 0.8 mm atmospheric windows
• Modeling the chemical evolution of a collapsing prestellar core in two spatial dimensions
• Fine and hyperfine excitation of nitric oxide by collision with para-H2
• The efficient photodesorption of nitric oxide (NO) ices A laboratory astrophysics study
• Probing the physical and chemical structure of the CS core in LDN 673. Multitransitional and continuum observations
• Problems of Star Formation Theory and Prospects of Submillimeter Observations