The essential elements of dust evolution

Abstract

Context. There remain many open questions relating to the depletion of elements into dust, e.g., exactly how are C and O incorporated into dust in dense clouds and, in particular, what drives the disappearance of oxygen in the denser interstellar medium? Aims. This work is, in part, an attempt to explain the apparently anomalous incorporation of O atoms into dust in dense clouds. Methods. We re-visit the question of the depletion of the elements incorporated into the carbonaceous component of interstellar dust, i.e., C, H, O, N and S, in the light of recent analyses of the organics in comets, meteorites and interplanetary dust particles. Results. We find that oxygen could be combined with ≈10–20 % of the carbon in the dust in dense regions in the form of a difficult to observe, organic carbonate, (−O−O>C =O), which could explain the unaccounted for 170–255 ppm oxygen depletion. Conclusions. We conclude that, while C, O and N atoms are depleted into an amorphous a-C:H:O:N phase, we posit that a significant fraction of C and O atoms could be sequestered into an organic carbonate, which provides a viable solution to the oxygen depletion problem. Further, the thermal or photolytic decomposition of this carbonate may have a bearing on the formation of CO2 in the ISM.

JINGLE – IV. Dust, H i gas, and metal scaling laws in the local Universe

“…rates (f survival of 37-89%) and low grain growth efficiencies ( of 30-40). These long grain growth timescales could reduce the tension between the high grain growth efficiencies (required to reproduce the large dust masses observed in lowto high-redshift galaxies) and grain surface chemical models, which currently fail to account for efficient grain growth processes in the interstellar medium (e.g., Barlow 1978;Ferrara et al 2016;Ceccarelli et al 2018;Jones & Ysard 2019).…”

“…We speculate that these models provide an alternative to earlier work that required vigorous dust destruction and efficient grain growth on timescales a few Myr (e.g., Draine 2009;Zhukovska 2014;Feldmann 2015;De Vis et al 2017b) to explain local galaxy scaling relations. These long dust lifetimes and reduced grain growth efficiencies could reduce the tension with grain-surface chemical models (e.g., Barlow 1978;Ferrara et al 2016;Ceccarelli et al 2018;Jones & Ysard 2019) that have not been able to come up with efficient grain growth mechanisms in interstellar clouds. Our model results might furthermore help solving the dust budget problem at high redshifts (e.g., Bertoldi et al 2003;Priddey et al 2003;Watson et al 2015), in case similar dust production and destruction efficiencies would apply to those primordial galaxies.…”

Physics and chemistry on the surface of cosmic dust grains: a laboratory view

“…It was shown that the photolysis of carbonates presented in the substrate was possibly a source of CO2, CO, carbon and oxygen atoms. Organic carbonates can form in the translucent ISM before the formation of molecular ices [273].…”

BEDE: Bayesian Estimates of Dust Evolution For Nearby Galaxies

“…When the molecular clouds are dissociated, the ice mantles evaporate and only ≈ 10 per cent of the cloud dust mass accreted in dense clouds survives as a refractory material in the transition into the diffuse ISM (Jones & Ysard, 2019). We set f dis = 0.1 (Equation 10) to account for this.…”