Laboratory Evidence for Efficient Water Formation in Interstellar Ices

By S. Ioppolo, H. Cuppen, C. Romanzin, E. V. van Dishoeck, H. Linnartz. 2008

212 citations recorded by the source corpus.

Even though water is the main constituent in interstellar icy mantles, its chemical origin is not well understood. Three different formation routes have been proposed following hydrogenation of O, O2, or O3 on icy grains, but experimental evidence is largely lacking. We present a solid state astrochemical laboratory study in which one of these routes is tested. For this purpose O2 ice is bombarded by H or D atoms under ultrahigh vacuum conditions at astronomically relevant temperatures ranging from 12 to 28 K. The use of reflection absorption infrared spectroscopy (RAIRS) permits derivation of reaction rates and shows efficient formation of H2O (D2O) with a rate that is surprisingly independent of temperature. This formation route converts O2 into H2O via H2O2 and is found to be orders of magnitude more efficient than previously assumed. It should therefore be considered as an important channel for interstellar water ice formation as illustrated by astrochemical model calculations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/5519399aaf40b0c00a83e0bc176a193deed247c7

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. R. Garrod
2. P. Caselli
3. E. Dishoeck
4. E. Herbst
5. Cecilia Ceccarelli
6. E. Bergin
7. K. Oberg
8. V. Wakelam

In Instrumentation

1. M. Tafalla
2. P. Caselli
3. E. Bergin
4. E. Dishoeck
5. E. Herbst
6. R. Garrod
7. Cecilia Ceccarelli
8. Y. Aikawa

Citations in the corpus

• ON THE FORMATION OF CO2 AND OTHER INTERSTELLAR ICES (2011, result): “This high efficiency is in line with experimental findings by Miyauchi et al. (2008), Ioppolo et al. (2008), and Oba et al. (2009) showing that O2 may be efficiently converted to water at low temperatures.”
• Formation rates of complex organics in UV irradiated CH3OH-rich ices I: Experiments (2009, background): “All fundamental H2O2 infrared bands completely overlap with strong CH3OH bands in the investigated spectral region (e.g. Loeffl r et al. 2006; Ioppolo et al. 2008).”
• Water in star-forming regions with Herschel (WISH). II. Evolution of 557 GHz 110-101 emission in low-mass protostars (2012, background): “In the molecular envelope from which the protostar accretes matter, water forms almost exclusively on the surfaces of dust grains (Tielens & Hagen 1982; Ioppolo et al. 2008) and it is the dominant ice constituent (Whittet et al. 1988; Pontoppidan et al. 2004).”
• Reaction Networks for Interstellar Chemical Modelling: Improvements and Challenges (2010, background): “The hydrogenation of solid O2 is the best studied channel (Miyauchi et al. 2008; Ioppolo et al. 2008; Oba et al. 2009).”
• Experimental evidence for water formation on interstellar dust grains by hydrogen and oxygen atoms (2009, background): “(Ioppolo et al. 2008) did a similar experiment but with varying O2 substrate temperatures.”
• Hydrogenation reactions in interstellar CO ice analogues A combined experimental/theoretical approach (2009, methodology): “Figure 1 shows a schematic representation of the setup (see Ioppolo et al. (2008) for additional information).”
• The Molecular Universe (2011, background): “Over the past 10 years, these theoretical ideas have been extensively investigated in the laboratory and the viability of this activation route of CO is now well established (Hiraoka et al. 1998; Hidaka et al. 2004; Fuchs et al. 2009; Ioppolo et al. 2008).”
• Water in Star-forming Regions with the Herschel Space Observatory (WISH). I. Overview of Key Program and First Results (2010, background): “Surface science laboratory experiments are only now starting to test these reactions experimentally (Ioppolo et al. 2008, 2010; Miyauchi et al. 2008; Dulieu et al. 2010; Romanzin et al. 2010).”
• Astrochemistry and compositions of planetary systems (2020, background): “2002; Watanabe and Kouchi 2002), and CO2 from CO and OH (Ioppolo et al. 2008; Miyauchi et al. 2008; Mokrane et al. 2009; Dulieu et al. 2010).”
• The molecular composition of the planet-forming regions of protoplanetary disks across the luminosity regime (2015, background): “Recent laboratory experiments have shown that the hydrogenation of O2 ice is rapid at low temperatures (Ioppolo et al. 2008; Miyauchi et al. 2008).”
• FIRST DETECTION OF WATER VAPOR IN A PRE-STELLAR CORE (2012, background): “Thus, it is now well established that water ice is formed on the surface of dust particles via hydrogenation of atomic and molecular oxygen (Ioppolo et al. 2008).”
• A UNIFIED REPRESENTATION OF GAS-PHASE ELEMENT DEPLETIONS IN THE INTERSTELLAR MEDIUM (2009, background): “(While it is abundant, the consumption of N during grain growth is nowhere near as much as O.) An initially attractive prospect was that O is incorporated in the form of amorphous H2O ice on the grain surfaces (Ioppolo et al. 2008).”
• PHOTODESORPTION OF ICES. II. H2O AND D2O (2008, background): “In cold, quiescent clouds H2O forms through hydrogenation of O (O2 or O3) on cold (sub)micron-sized silicate grain surfaces forming icy layers (Tielens & Hagen 1982; Léger et al. 1985; Boogert & Ehrenfreund 2004; Miyauchi et al. 2008; Ioppolo et al. 2008).”
• Our astrochemical heritage (2012, background): “When colliding with dust grains, they can alter mantle compositions (e.g., Palumbo et al. 2000; Ioppolo et al. 2009; Modica and Palumbo 2010; Sicilia et al. 2012; Boduch et al. 2012; Pilling et al. 2012).”