Detection of the hydroperoxyl radical HO<sub>2</sub>toward<i>ρ</i>Ophiuchi A

Parise, B.; Bergman, P.; Du, Fujun

doi:10.1051/0004-6361/201219379

Cited by 51 publications

(44 citation statements)

References 26 publications

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“…We computed the chemical composition of a cloud with similar physical characteristics as ρ Oph A to reproduce species such as HO 2 and H 2 O 2 , which have been observed in this environment (Bergman et al 2011;Parise et al 2012). We show that the presence of HO 2 and H 2 O 2 in interstellar gas indicates that species are starting to freeze out.…”

Section: Discussionmentioning

confidence: 91%

“…Observations of H 2 O 2 and HO 2 in ρ Oph A show that the abundances of these species are ∼10 −10 each (Bergman et al 2011;Parise et al 2012). Methanol has also been observed with an abundance of ∼10 −9 Liseau et al (2003), Bergman et al (2011).…”

Section: Discussionmentioning

confidence: 97%

“…Our study is motivated by the recent detections of O 2 , HO 2 and H 2 O 2 in ρ Oph A (Bergman et al 2011;Parise et al 2012;Liseau et al 2012) and of O 2 in Orion (Goldsmith et al 2011). The detections of O 2 in these two distinct environments have been attributed to the effect of warm dust grains that allow the evaporation of the ices covering the dust.…”

Section: Simulationsmentioning

confidence: 99%

“…Observations of ρ Oph A reported the presence of species such as O 2 , HO 2 , and H 2 O 2 (Bergman et al 2011;Parise et al 2012;Liseau et al 2012) that could be attributed to the effect of warm dust allowing the evaporation of their ices. In particular, the detection of H 2 O 2 in ρ Oph A, a molecule that is known to be present in ices but has never been observed before, raised the question of its origin.…”

Section: Introductionmentioning

confidence: 99%

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Dust as interstellar catalyst

Cazaux

Minissale

Dulieu

et al. 2015

A&A

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Context. Interstellar dust particles, which represent 1% of the total mass, are recognized to be very powerful interstellar catalysts in star-forming regions. The presence of dust can have a strong impact on the chemical composition of molecular clouds. While observations show that many species that formed onto dust grains populate the gas phase, the process that transforms solid state into gas phase remains unclear. Aims. The aim of this paper is to consider the chemical desorption process, i.e. the process that releases solid species into the gas phase, in astrochemical models. These models allow determining the chemical composition of star-forming environments with an accurate treatment of the solid-phase chemistry. Methods. In paper I we derived a formula based on experimental studies with which we quantified the efficiencies of the chemical desorption process. Here we extend these results to astrophysical conditions. Results. The simulations of astrophysical environments show that the abundances of gas-phase methanol and H 2 O 2 increase by four orders of magnitude, whereas gas-phase H 2 CO and HO 2 increase by one order of magnitude when the chemical desorption process is taken into account. The composition of the ices strongly varies when the chemical desorption is considered or neglected. Conclusions. We show that the chemical desorption process, which directly transforms solid species into gas-phase species, is very efficient for many reactions. Applied to astrophysical environments such as ρ Oph A, we show that the chemical desorption efficiencies derived in this study reproduce the abundances of observed gas-phase methanol, HO 2 , and H 2 O 2 , and that the presence of these molecules in the gas shows the last signs of the evolution of a cloud before the frost.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 97%

Section: Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dust as interstellar catalyst

Cazaux

Minissale

Dulieu

et al. 2015

A&A

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“…Most notably, these include complex organic molecules (Bacmann et al 2012), carbonyl sulfide (Palumbo et al 1997), hydrogen peroxide and hydroperoxyl radical O 2 H (Bergman et al 2011;Parise et al 2012). This coincidence may point out either to CR-induced processing of interstellar ices, or efficient coupling between the surface and the mantle, as indicated also by Garrod (2013a).…”

Section: Discussionmentioning

confidence: 99%

Cosmic-Ray Induced Diffusion in Interstellar Ices

Kalvāns

2014

Open Astronomy

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Abstract.Cosmic rays are able to heat interstellar dust grains. This may enhance molecule mobility in icy mantles that have accumulated on the grains in dark cloud cores. A three-phase astrochemical model was used to investigate the molecule mobility in interstellar ices. Specifically, diffusion through pores in ice between the subsurface mantle and outer surface, assisted by whole-grain heating, was considered. It was found that the pores can serve as an efficient transport route for light species. The diffusion of chemical radicals from the mantle to the outer surface are most effective. These species accumulate in the mantle because of photodissociation by the cosmic-ray induced photons. The faster diffusion of hydrogen within the warm ice enhances the hydrogenation of radicals on pore surfaces. The overall result of the whole grain heating-induced radial diffusion in ice are higher abundances of ice species, whose synthesis involve light radicals. Examples of stable species synthesized this way include complex organic molecules, OCS, H 2 O 2 and cyanoplyynes.

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On the formation of propylene oxide from propylene in space: gas-phase reactions

Bodo¹,

Bovolenta²,

Simha³

et al. 2019

Theor Chem Acc

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In the present article we have investigated the possibility of forming propylene oxide (PO) from propylene (PE) by bi-molecular reactions. Propylene oxide is the first chiral molecule observed in the interstellar medium, and studying the thermodynamics and kinetics of formation can suggest possible synthetic routes. We have focused our attention on gas phase reactions, and the presence of an environment is discussed in particular for the possibility of forming it by association reactions. In particular, we have considered radical and ion-molecule reactions. Results show that the main gas-phase route to PO formation is represented by ion-molecule reactions which turn out to be compatible with astrophysical conditions, notably: PE + O + and PE + HO + 2. Their final product is not PO, but its ionized variant PO + that can be neutralized by electron capture. The only thermodynamically and kinetically allowed reaction which can directly lead to neutral PO is a collision of PE with a singlet-excited OH + but two competing reactions (leading to PE + and PO +) are thermodynamically favored and thus more plausible in space.

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Detection of the hydroperoxyl radical HO₂towardρOphiuchi A

Cited by 51 publications

References 26 publications

Dust as interstellar catalyst

Dust as interstellar catalyst

Cosmic-Ray Induced Diffusion in Interstellar Ices

On the formation of propylene oxide from propylene in space: gas-phase reactions

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Detection of the hydroperoxyl radical HO2towardρOphiuchi A

Cited by 51 publications

References 26 publications

Dust as interstellar catalyst

Dust as interstellar catalyst

Cosmic-Ray Induced Diffusion in Interstellar Ices

On the formation of propylene oxide from propylene in space: gas-phase reactions

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Detection of the hydroperoxyl radical HO₂towardρOphiuchi A