Role of NH3 Binding Energy in the Early Evolution of Protostellar Cores

Abstract

NH${}_3$(ammonia) plays a critical role in the chemistry of star and planet formation, yet uncertainties in its binding energy (BE) values complicate accurate estimates of its abundances. Recent research suggests a multi-binding energy approach, challenging the previous single-value notion. In this work, we use different values of NH${}_3$ binding energy to examine its effects on the NH${}_3$ abundances and, consequently, in the early evolution of protostellar cores. Using a gas-grain chemical network, we systematically vary the values of NH${}_3$ binding energies in a model Class 0 protostellar core and study the effects of these binding energies on the NH${}_3$ abundances. Our simulations indicate that abundance profiles of NH${}_3$ are highly sensitive to the binding energy used, particularly in the warmer inner regions of the core. Higher binding energies lead to lower gas-phase NH${}_3$ abundances, while lower values of binding energy have the opposite effect. Furthermore, this BE-dependent abundance variation of NH${}_3$ significantly affects the formation pathways and abundances of key species such as HNC, HCN, and CN. Our tests also reveal that the size variation of the emitting region due to binding energy becomes discernible only with beam sizes of 10 arcsec or less. These findings underscore the importance of considering a range of binding energies in astrochemical models and highlight the need for higher resolution observations to better understand the subtleties of molecular cloud chemistry and star formation processes.

References in corpus (36)

• An atomic and molecular database for analysis of submillimetre line observations
• Observations of the Icy Universe
• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• Systematic Molecular Differentiation in Starless Cores
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• The 2014 KIDA network for interstellar chemistry
• Observing the gas temperature drop in the high-density nucleus of L 1544
• Binding energies: new values and impact on the efficiency of chemical desorption
• Dynamics and Depletion in Thermally Supercritical Starless Cores
• Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids
• Depletion and low gas temperature in the L183 prestellar core : the N2H+ - N2D+ tool
• Formation and recondensation of complex organic molecules during protostellar luminosity outbursts
• Binding energies of interstellar molecules on crystalline and amorphous models of water ice by ab-initio calculations
• Sensitivity analysis of grain surface chemistry to binding energies of ice species
• HCN/HNC intensity ratio: a new chemical thermometer for the molecular ISM
• Benchmarking spin-state chemistry in starless core models
• The solar type protostar IRAS16293-2422: new constraints on the physical structure
• The Central 1000 au of a Pre-stellar Core Revealed with ALMA. II. Almost Complete Freeze-out
• Binding Energy of Molecules on Water Ice: Laboratory Measurements and Modeling
• On the Ortho:Para Ratio of H3+ in Diffuse Molecular Clouds
• First detection of gas-phase ammonia in a planet-forming disk
• Dense Gas Tracers in Perseus: Relating the N2H+, NH3, and Dust Continuum Properties of Pre- and Proto-Stellar Cores
• Spin-state chemistry of deuterated ammonia
• Nascent bipolar outflows associated with the first hydrostatic core candidates Barnard 1b-N and 1b-S
• Orbital and mass constraints of the young binary system IRAS 16293-2422 A
• Modelling line emission of deuterated H_3^+ from prestellar cores
• Chemical and physical characterization of collapsing low-mass prestellar dense cores
• Detection of interstellar ortho-D2H+ with SOFIA
• An Interferometric View of H-MM1. I. Direct Observation of NH3 Depletion
• A novel framework to study the impact of binding energy distributions on the chemistry of dust grains
• LOC program for line radiative transfer
• Survey of Water and Ammonia in Nearby galaxies (SWAN): Resolved Ammonia Thermometry, and Water and Methanol Masers in IC 342, NGC 6946 and NGC 2146
• Radial molecular abundances and gas cooling in starless cores
• Similar levels of deuteration in the pre-stellar core L1544 and the protostellar core HH211
• Odin observations of ammonia in the Sgr A +50 km/s Cloud and Circumnuclear Disk