English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The quantity of NH3 produced on grain surfaces in the prestellar core isthought to be one of the determining factors regarding the chemical complexityachievable at later stages of stellar birth. In order to investigate how thisquantity might be influenced by the gas-grain cycling of molecular materialwithin the cloud, we employ a modified rates gas-grain chemical code and followthe time-dependent chemistry of NH3 as the system evolves. Our modelsincorporate an updated version of the most recent UDfA network of reaction ratecoefficients, desorption from the grains through standard thermal andnon-thermal processes, and physisorbed and chemisorbed binding of atomic andmolecular hydrogen to a population of carbonaceous and siliceous grains. Wefind that 1.) observable abundances of NH3 can exist in the gas phase of ourmodels at early times when the N atom is derived from CN via an efficientearly-time hydrocarbon chemistry, 2.) a time-dependent gradient exists in theobservational agreement between different species classes in our models,consistent with possible physical substructures within the TMC-1 CyanopolyynePeak, and 3.) the gaseous and solid-state abundances of NH3 are sensitive tothe presence of gas-grain cycling within the system. Our results suggest thatthe degree of chemical complexity achievable at later stages of the cloud'schemical evolution is indeed influenced by the manner in which the gas-graincycling occurs.

Species cycling and the enhancement of ammonia in prestellar cores