On the formation of complex organic molecules in the interstellar medium: untangling the chemical complexity of carbon monoxide–hydrocarbon containing ice analogues exposed to ionizing radiation via a combined infrared and reflectron time-of-flight analysis

2019 ◽  
Vol 21 (31) ◽  
pp. 16949-16980 ◽  
Author(s):  
Matthew J. Abplanalp ◽  
Ralf I. Kaiser
Keyword(s):  
Carbon Monoxide ◽  
Ionizing Radiation ◽  
Interstellar Medium ◽  
Organic Molecules ◽  
Time Of Flight ◽  
Specific Detection ◽  
Chemical Complexity ◽  
Complex Organic

The isomer specific detection of complex organic molecules from irradiated carbon monoxide–hydrocarbon ices and their yields have been elucidated.

Formation of complex organic molecules in methanol and methanol–carbon monoxide ices exposed to ionizing radiation – a combined FTIR and reflectron time-of-flight mass spectrometry study

2015 ◽  
Vol 17 (5) ◽  
pp. 3081-3114 ◽  
Author(s):  
Surajit Maity ◽  
Ralf I. Kaiser ◽  
Brant M. Jones
Keyword(s):  
Carbon Monoxide ◽  
Ionizing Radiation ◽  
Organic Molecules ◽  
Temperature Programmed Desorption ◽  
Chemical Processing ◽  
Flight Mass Spectrometry ◽  
Mass Spectrometry Study ◽  
Radiation Induced ◽  
Temperature Programmed ◽  
Complex Organic

The radiation induced chemical processing of methanol and methanol–carbon monoxide ices at 5.5 K exposed to ionizing radiation in the form of energetic electrons and subsequent temperature programmed desorption is reported in this study.

scholarly journals Chemical complexity in the Horsehead photodissociation region

2014 ◽  
Vol 168 ◽  
pp. 103-127 ◽  
Author(s):  
Viviana V. Guzmán ◽  
Jérôme Pety ◽  
Pierre Gratier ◽  
Javier R. Goicoechea ◽  
Maryvonne Gerin ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Gas Phase ◽  
Thermal Desorption ◽  
Organic Molecules ◽  
Dense Core ◽  
High Spectral Resolution ◽  
Complex Molecules ◽  
Chemical Complexity ◽  
Clean Environment ◽  
Complex Organic

The interstellar medium is known to be chemically complex. Organic molecules with up to 11 atoms have been detected in the interstellar medium, and are believed to be formed on the ices around dust grains. The ices can be released into the gas-phase either through thermal desorption, when a newly formed star heats the medium around it and completely evaporates the ices; or through non-thermal desorption mechanisms, such as photodesorption, when a single far-UV photon releases only a few molecules from the ices. The first mechanism dominates in hot cores, hot corinos and strongly UV-illuminated PDRs, while the second dominates in colder regions, such as low UV-field PDRs. This is the case of the Horsehead were dust temperatures are ≃20–30 K, and therefore offers a clean environment to investigate the role of photodesorption. We have carried out an unbiased spectral line survey at 3, 2 and 1mm with the IRAM-30m telescope in the Horsehead nebula, with an unprecedented combination of bandwidth, high spectral resolution and sensitivity. Two positions were observed: the warm PDR and a cold condensation shielded from the UV field (dense core), located just behind the PDR edge. We summarize our recently published results from this survey and present the first detection of the complex organic molecules HCOOH, CH2CO, CH3CHO and CH3CCH in a PDR. These species together with CH3CN present enhanced abundances in the PDR compared to the dense core. This suggests that photodesorption is an efficient mechanism to release complex molecules into the gas-phase in far-UV illuminated regions.

scholarly journals A Photoionization Mass Spectrometry Investigation into Complex Organic Molecules Formed in Interstellar Analog Ices of Carbon Monoxide and Water Exposed to Ionizing Radiation

2021 ◽  
Vol 916 (2) ◽  
pp. 74
Author(s):  
Andrew M. Turner ◽  
Alexandre Bergantini ◽  
Andreas S. Koutsogiannis ◽  
N. Fabian Kleimeier ◽  
Santosh K. Singh ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Carbon Monoxide ◽  
Ionizing Radiation ◽  
Organic Molecules ◽  
Photoionization Mass Spectrometry ◽  
Complex Organic

Thermal and photochemical study of CH3OH and CH3OH–O2 astrophysical ices

2020 ◽  
Vol 500 (1) ◽  
pp. 1188-1200
Author(s):  
Killian Leroux ◽  
Lahouari Krim
Keyword(s):  
Interstellar Medium ◽  
Organic Compounds ◽  
Organic Molecules ◽  
Uv Light ◽  
Hydrogen Abstraction ◽  
Insertion Reaction ◽  
Abstraction Reaction ◽  
Uv Photons ◽  
Astrophysical Ices ◽  
Complex Organic

ABSTRACT Methanol, which is one of the most abundant organic molecules in the interstellar medium, plays an important role in the complex grain surface chemistry that is believed to be a source of many organic compounds. Under energetic processing such as ultraviolet (UV) photons or cosmic rays, methanol may decompose into CH4, CO2, CO, HCO, H2CO, CH3O and CH2OH, which in turn lead to complex organic molecules such as CH3OCHO, CHOCH2OH and HOCH2CH2OH through radical recombination reactions. However, although molecular oxygen and its detection, abundance and role in the interstellar medium have been the subject of many debates, few experiments on the oxidation of organic compounds have been carried out under interstellar conditions. The present study shows the behaviour of solid methanol when treated by UV light and thermal processing in oxygen-rich environments. Methanol has been irradiated in the absence and presence of O2 at different concentrations in order to study how oxidized complex organic molecules may form and also to investigate the O-insertion reaction in the C–H bound to form methanediol HOCH2OH through a CH3OH + O(1D) solid-state reaction. The adding of O2 in the thermal and photochemical reaction of solid methanol leads to the formation of O3, H2O and HO2, in addition to three main organics, HCOOH, CHOCHO and HOCH2OH. We show that in an O2-rich environment, species such as CO, CH4, HCO, CH3OH and CHOCH2OH are oxidized into CO2, CH3OH, HC(O)OO, HOCH2OH and CHOCHO, respectively, while HCOOH might be formed through the H2CO + O(3P) → (OH + HCO)cage → HCOOH hydrogen-abstraction reaction.

Extraterrestrial Molecules: Present and Future Observations from Space

1979 ◽  
Vol 47 ◽  
pp. 439-456
Author(s):  
Cristiano Batalli Cosmovici
Keyword(s):  
Interstellar Medium ◽  
Interdisciplinary Research ◽  
Organic Molecules ◽  
Space Astronomy ◽  
Cool Stars ◽  
Infrared Studies ◽  
The Galaxy ◽  
Molecular Astrophysics ◽  
Complex Organic ◽  
Atmospheric Windows

AbstractIn the last ten years Molecular Astrophysics has become an extremely interesting field of interdisciplinary research as a result of unexpected discoveries of complex organic molecules made by radioastronomy in many regions and objects of the Galaxy. Since not all molecules have detectable transitions through the atmospheric windows, the development of UV and IR space astronomy will allow us to study new important molecular transitions in the interstellar medium and in the atmospheres of cool stars and comets. In this paper the present status of molecular astrophysics will be described and special emphasis will be devoted to the importance of IR space astronomy for the future knowledge of molecular species in the interstellar medium and in the atmospheres of Carbon stars where the low temperatures are particularly, suitable for infrared studies

scholarly journals Interstellar Methanol from the Lab to Protoplanetary Disks

2015 ◽  
Vol 11 (A29A) ◽  
Author(s):  
Maria N. Drozdovskaya ◽  
Catherine Walsh ◽  
Ruud Visser ◽  
Daniel Harsono ◽  
Ewine F. van Dishoeck
Keyword(s):  
Organic Molecules ◽  
Disk Formation ◽  
Chemical Complexity ◽  
Chemical Models ◽  
Collapse Model ◽  
Low Mass ◽  
Grain Surface ◽  
Physical And Chemical ◽  
Complex Organic ◽  
Insight Into

Interstellar methanol is thought to be the precursor of larger, more complex organic molecules. It holds a central role in many astrochemical models (e.g., Garrod & Herbst 2006). Methanol has also been the focus of several laboratory studies (e.g., Watanabe et al. 2004, Fuchs et al. 2009), in an effort to gain insight into grain-surface chemistry, which potentially builds chemical complexity already in the cold, dark prestellar phase. The case of methanol is a prime example of experimental work having implications on astronomical scales. Drozdovskaya et al. (2014) unified physical and chemical models to simulate infalling material during the birth of a low-mass protostar. An axisymmetric 2D semi-analytic collapse model (Visser et al. 2009), wavelength-dependent radiative transfer calculations with RADMC3D (Dullemond & Dominik 2004) and a comprehensive gas-grain chemical network (Walsh et al. 2014) were used to study two modes of protoplanetary disk formation.

scholarly journals Systems Astrochemistry: A New Doctrine for Experimental Studies

2021 ◽  
Vol 8 ◽  
Author(s):  
Nigel J. Mason ◽  
Perry A. Hailey ◽  
Duncan V. Mifsud ◽  
James S. Urquhart
Keyword(s):  
Experimental Design ◽  
Interstellar Medium ◽  
Laboratory Experiments ◽  
Organic Molecules ◽  
Prebiotic Chemistry ◽  
Experimental Studies ◽  
Experimental Parameter ◽  
Complex Organic ◽  
Insight Into ◽  
Reductionist Approach

Laboratory experiments play a key role in deciphering the chemistry of the interstellar medium (ISM) and the formation of complex organic molecules (COMs) relevant to life. To date, however, most studies in experimental astrochemistry have made use of a reductionist approach to experimental design in which chemical responses to variations in a single parameter are investigated while all other parameters are held constant. Although such work does afford insight into the chemistry of the ISM, it is likely that several important points (e.g., the possible influence of experimental parameter interaction) remain ambiguous. In light of this, we propose the adoption of a new “systems astrochemistry” approach for experimental studies and present the basic tenants and advantages of this approach in this perspective article. Such an approach has already been used for some time now and to great effect in the field of prebiotic chemistry, and so we anticipate that its application to experimental astrochemistry will uncover new data hitherto unknown which could aid in better linking laboratory work to observations and models.

scholarly journals Complex organic molecules along the accretion flow in isolated and externally irradiated protoplanetary disks

2014 ◽  
Vol 168 ◽  
pp. 389-421 ◽  
Author(s):  
Catherine Walsh ◽  
Eric Herbst ◽  
Hideko Nomura ◽  
T. J. Millar ◽  
Susanna Widicus Weaver
Keyword(s):  
Surface Chemistry ◽  
Gas Phase ◽  
Organic Molecules ◽  
Molecular Layer ◽  
Accretion Flow ◽  
Chemical Complexity ◽  
Outer Disk ◽  
Molecular Abundances ◽  
Grain Surface ◽  
Complex Organic

The birth environment of the Sun will have influenced the physical and chemical structure of the pre-solar nebula, including the attainable chemical complexity reached in the disk, important for prebiotic chemistry. The formation and distribution of complex organic molecules (COMs) in a disk around a T Tauri star is investigated for two scenarios: (i) an isolated disk, and (ii) a disk irradiated externally by a nearby massive star. The chemistry is calculated along the accretion flow from the outer disk inwards using a comprehensive network which includes gas-phase reactions, gas-grain interactions, and thermal grain-surface chemistry. Two simulations are performed, one beginning with complex ices and one with simple ices only. For the isolated disk, COMs are transported without major chemical alteration into the inner disk where they thermally desorb into the gas reaching an abundance representative of the initial assumed ice abundance. For simple ices, COMs can efficiently form on grain surfaces under the conditions in the outer disk. Gas-phase COMs are released into the molecular layer via photodesorption. For the irradiated disk, complex ices are also transported inwards; however, they undergo thermal processing caused by the warmer conditions in the irradiated disk which tends to reduce their abundance along the accretion flow. For simple ices, grain-surface chemistry cannot efficiently synthesise COMs in the outer disk because the necessary grain-surface radicals, which tend to be particularly volatile, are not sufficiently abundant on the grain surfaces. Gas-phase COMs are formed in the inner region of the irradiated disk via gas-phase chemistry induced by the desorption of strongly bound molecules such as methanol; hence, the abundances are not representative of the initial molecular abundances injected into the outer disk. These results suggest that the composition of comets formed in isolated disks may differ from those formed in externally irradiated disks with the latter composed of more simple ices.

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