Desorption of CO and O2 interstellar ice analogs
arXiv:astro-ph/0702322 · doi:10.1051/0004-6361:20066272
Abstract
Solid O2 has been proposed as a possible reservoir for oxygen in dense clouds through freeze-out processes. The aim of this work is to characterize quantitatively the physical processes that are involved in the desorption kinetics of CO-O2 ices by interpreting laboratory temperature programmed desorption (TPD) data. This information is used to simulate the behavior of CO-O2 ices under astrophysical conditions. The TPD spectra have been recorded under ultra high vacuum conditions for pure, layered and mixed morphologies for different thicknesses, temperatures and mixing ratios. An empirical kinetic model is used to interpret the results and to provide input parameters for astrophysical models. Binding energies are determined for different ice morphologies. Independent of the ice morphology, the desorption of O2 is found to follow 0th-order kinetics. Binding energies and temperature-dependent sticking probabilities for CO-CO, O2-O2 and CO-O2 are determined. O2 is slightly less volatile than CO, with binding energies of 912+-15 versus 858+-15 K for pure ices. In mixed and layered ices, CO does not co-desorb with O2 but its binding energies are slightly increased compared with pure ice whereas those for O2 are slightly decreased. Lower limits to the sticking probabilities of CO and O2 are 0.9 and 0.85, respectively, at temperatures below 20K. The balance between accretion and desorption is studied for O2 and CO in astrophysically relevant scenarios. Only minor differences are found between the two species, i.e., both desorb between 16 and 18K in typical environments around young stars. Thus, clouds with significant abundances of gaseous CO are unlikely to have large amounts of solid O2.
8 pages + 2 pages online material, 8 figures (1 online), accepted by A&A
References in corpus (4)
Cited by in corpus (53)
- Formation rates of complex organics in UV irradiated CH3OH-rich ices I: Experiments
- 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
- Photodesorption of Ices II: H2O and D2O
- Reaction Networks For Interstellar Chemical Modelling: Improvements and Challenges
- Laboratory evidence for efficient water formation in interstellar ices
- Chemistry in Disks. IV. Benchmarking gas-grain chemical models with surface reactions
- Atom addition reactions in interstellar ice analogues
- Herschel Measurements of Molecular Oxygen in Orion
- Oxygen Depletion in the Interstellar Medium: Implications for Grain Models and the Distribution of Elemental Oxygen
- Water formation at low temperatures by surface O2 hydrogenation II: the reaction network
- The chemical history of molecules in circumstellar disks. II. Gas-phase species
- Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores
- Thermal desorption characteristics of CO, O2 and CO2 on non-porous water, crystalline water and silicate surfaces at sub-monolayer and multilayer coverages
- CO destruction in protoplanetary disk midplanes: inside versus outside the CO snow surface
- Formation and recondensation of complex organic molecules during protostellar luminosity outbursts
- Sensitivity analysis of grain surface chemistry to binding energies of ice species
- The 13O-rich atmosphere of a young accreting super-Jupiter
- Water formation at low temperatures by surface O2 hydrogenation I: characterization of ice penetration
- CO and N desorption energies from water ice
- A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the ISM
- Low Temperature Surface Formation of NH3 and HNCO: hydrogenation of nitrogen atoms in CO-rich interstellar ice analogues
- A primordial origin for molecular oxygen in comets: A chemical kinetics study of the formation and survival of O ice from clouds to disks
- The thermal reactivity of HCN and NH3 in interstellar ice analogues
- Deep observations of O2 toward a low-mass protostar with Herschel-HIFI
- Hydrogenation at low temperatures does not always lead to saturation: the case of HNCO
- Photochemistry of the PAH pyrene in water ice: the case for ion-mediated solid-state astrochemistry
- Sticking coefficient of hydrogen and deuterium on silicates under interstellar conditions
- The 12CO/13CO isotopologue ratio of a young, isolated brown dwarf. Possibly distinct formation pathways of super-Jupiters and brown dwarfs
- Heterogeneity in CO/CO Ratios Toward Solar-Type Young Stellar Objects
- Chemical and physical characterization of collapsing low-mass prestellar dense cores
- Band profiles and band strengths in mixed H2O:CO ices
- Temperature programed desorption of water ice from the surface of amorphous carbon and silicate grains as related to planet-forming disks
- Ammonia snow-lines and ammonium salts desorption
- Methanol ice co-desorption as a mechanism to explain cold methanol in the gas-phase
- The Ice Chamber for Astrophysics-Astrochemistry (ICA): A New Experimental Facility for Ion Impact Studies of Astrophysical Ice Analogues
- CO depletion: a microscopic perspective
- A new model of the chemistry of ionizing radiation in solids: CIRIS
- Thermal desorption of astrophysically relevant molecules from forsterite(010)
- Vacuum ultraviolet photoabsorption spectroscopy of space-related ices: Formation and destruction of solid carbonic acid upon 1~keV electron irradiation
- M-Band Spectra of Dust Embedded Sources at the Galactic Center
- Fitting infrared ice spectra with genetic modelling algorithms. Presenting the ENIIGMA fitting tool
- Predicting binding energies of astrochemically relevant molecules via machine learning
- Modeling the chemical evolution of a collapsing prestellar core in two spatial dimensions
- Photodesorption of water ice from dust grains and thermal desorption of cometary ices studied by the INSIDE experiment
- A Search for O_2 in CO-depleted Molecular Cloud Cores with Herschel
- Ice mantles on dust grains: dramatic variation of thickness with grain size
- Thermal Behavior of Astrophysical Amorphous Molecular Ices
- On the origin of molecular oxygen on the surface of Ganymede
- Linking ice and gas in the Lambda Orionis Barnard 35A cloud
- Understanding the impact of diffusion of CO in the astrochemical models
- Simulation of CHOH ice UV photolysis under laboratory conditions
- A multigrain-multilayer astrochemical model with variable desorption energy for surface species
- HCN snowlines in protoplanetary disks: constraints from ice desorption experiments