CO2 Ice Research Articles

Photochemical Processes in CO2/H2O Ice Mixtures with Trapped Pyrene, a Model Polycyclic Aromatic Hydrocarbon

Abstract Vacuum ultraviolet irradiation of a polycyclic aromatic hydrocarbon molecule, pyrene, trapped in carbon dioxide (CO2)-enriched astrophysical ice analogues has been studied and presented here. Pyrene is co-deposited with a gaseous mixture of H2O and CO2 (100% CO2; 50:50 CO2:H2O; and 100% H2O) and is subjected to Ly α photons from a hydrogen-flow microwave discharge lamp. To our surprise, we found ionization of pyrene in all three ices, with ionization yields following the H2O content in the ice, indicating that H2O ice stabilizes charged ions and electrons better than CO2 ice by a factor of 10. Caution needs to be exercised not to overinterpret our finding that pyrene is ionized in pure CO2 ice, because even trace amounts of water in the CO2 matrix could result in an increased ionization of pyrene. In addition to ionization of pyrene in CO2 ice, photochemical products of the CO2 ice itself, namely CO and CO3, were found to form efficiently, as detected using Fourier transform infrared spectroscopy, in agreement with earlier studies. UV–vis spectra showed formation of ozone (O3) with prolonged irradiation. Surprisingly, O3 yields followed CO2 concentration in the ice mixtures, with the strongest bands in photolyzed CO2 ice and the weakest in photolyzed H2O ice, indicating that CO2 ice is very protoreactive and produces more O atoms than H2O ice. Pyrene-containing photoproducts, incorporating CO2 or CO or O, such as Py-COOH, Py-OH, or Py-CHO, are not explicitly seen in the UV–vis absorption spectra, but we cannot rule out the possibility that their UV absorption may be swamped under the strong absorption of O3.

H2chemistry in interstellar ices: the case of CO ice hydrogenation in UV irradiated CO:H2ice mixtures

Context.In dense clouds, hydrogenation reactions on icy dust grains are key in the formation of molecules, like formaldehyde, methanol, and complex organic molecules (COMs). These species form through the sequential hydrogenation of CO ice. Although molecular hydrogen (H2) abundances can be four orders of magnitude higher than those of free H-atoms in dense clouds, H2surface chemistry has been largely ignored; several laboratory studies show that H2does not actively participate in “non-energetic” ice chemistry because of the high activation energies required.Aims.For the example of CO ice hydrogenation, we experimentally investigated the potential role of H2molecules on the surface chemistry when energetic processing (i.e., UV photolysis) is involved. We test whether additional hydrogenation pathways become available upon UV irradiation of a CO:H2ice mixture and whether this reaction mechanism also applies to other chemical systems.Methods.Ultra-high vacuum (UHV) experiments were performed at 8–20 K. A pre-deposited solid mixture of CO:H2was irradiated with UV-photons. Reflection absorption infrared spectroscopy (RAIRS) was used as an in situ diagnostic tool. Single reaction steps and possible isotopic effects were studied by comparing results from CO:H2and CO:D2ice mixtures.Results.After UV-irradiation of a CO:H2ice mixture, two photon-induced products, HCO and H2CO, are unambiguously detected. The proposed reaction mechanism involves electronically excited CO in the following reaction steps: CO + hν→CO*, CO*+ H2→HCO + H where newly formed H-atoms are then available for further hydrogenation reactions. The HCO formation yields have a strong temperature dependence for the investigated regime, which is most likely linked to the H2sticking coefficient. Moreover, the derived formation cross section reflects a cumulative reaction rate that mainly determined by both the H-atom diffusion rate and initial concentration of H2at 8–20 K and that is largely determined by the H2sticking coefficient. Finally, the astronomical relevance of this photo-induced reaction channel is discussed.

Planet Four: Probing springtime winds on Mars by mapping the southern polar CO2 jet deposits

The springtime sublimation process of Mars’ southern seasonal polar CO2 ice cap features dark fan-shaped deposits appearing on the top of the thawing ice sheet. The fan material likely originates from the surface below the ice sheet, brought up via CO2 jets breaking through the seasonal ice cap. Once the dust and dirt is released into the atmosphere, the material may be blown by the surface winds into the dark streaks visible from orbit. The location, size and direction of these fans record a number of parameters important to quantifying seasonal winds and sublimation activity, the most important agent of geological change extant on Mars. We present results of a systematic mapping of these south polar seasonal fans with the Planet Four online citizen science project. Planet Four enlists the general public to map the shapes, directions, and sizes of the seasonal fans visible in orbital images. Over 80,000 volunteers have contributed to the Planet Four project, reviewing 221 images, from Mars Reconnaissance Orbiter’s HiRISE (High Resolution Imaging Science Experiment) camera, taken in southern spring during Mars Years 29 and 30. We provide an overview of Planet Four and detail the processes of combining multiple volunteer assessments together to generate a high fidelity catalog of ∼ 400000 south polar seasonal fans. We present the results from analyzing the wind directions at several locations monitored by HiRISE over two Mars years, providing new insights into polar surface winds.

The formation and stability of buried polar CO2 deposits on Mars

Shallow Radar soundings of the south polar layered deposits (SPLD) have revealed buried CO2 ice with as many as three distinct layers separated by thinner layers of water ice (Bierson et al., 2016). This layering is suggestive of formation by cyclical processes such as obliquity, eccentricity and advance of perihelion. If obliquity is the main driver, then there were many opportunities for CO2 deposits to have formed within the last 3.5-4 Myr. To persist, however, CO2 deposits must be followed by the deposition of an insulating layer of porous water ice that can seal in the CO2 to survive the obliquity maxima that follow. We suggest that the existing deposits were formed within the last 350 kyr. Each obliquity minimum was quickly followed by a period in which perihelion occurred in the northern summer (southern winter) solstice. Under these conditions, an enhanced deposition of low porosity, fine-grained water ice could occur on the winter pole. A similar series of depositions and burials by water ice could have occurred between 2.75 and 2.2 million years ago, but these deposits were unlikely to have survived the many high obliquity swings that occurred between 2.2 Ma and 400 ka. The formation and burial of CO2 ice could also have occurred in similar fashion earlier during the last ∼ 100 Myr in which the southern polar layered deposits were formed. Although at current times the geothermal flux may be too low to cause basal melting of CO2 deposits, in earlier times, deposits formed in deeper scarps and valleys could have led to basal CO2 melting and sequestration into the regolith. By extension, basal melting and sequestration in the regolith may provide an explanation for the fate of the thick CO2 atmosphere (pCO2 ≳ 0.5 bar) implied by climate models of early Mars.

A Subarcsecond ALMA Molecular Line Imaging Survey of the Circumbinary, Protoplanetary Disk Orbiting V4046 Sgr

Abstract We present a suite of Atacama Large Millimeter Array (ALMA) interferometric molecular line and continuum images that elucidate, on linear size scales of ∼30–40 au, the chemical structure of the nearby, evolved, protoplanetary disk orbiting the close binary system V4046 Sgr. The observations were undertaken in the 1.1–1.4 mm wavelength range (ALMA Bands 6 and 7) with antenna configurations involving maximum baselines of several hundred meters, yielding subarcsecond-resolution images in more than a dozen molecular species and isotopologues. Isotopologues of CO and HCN display centrally peaked morphologies of integrated emission-line intensity, whereas the line emission from complex nitrile group molecules (HC3N, CH3CN), deuterated molecules (DCN, DCO+), hydrocarbons (as traced by C2H), and potential CO ice line tracers (N2H+, and H2CO) appears as a sequence of sharp and diffuse rings. The dimensions and morphologies of HC3N and CH3CN emission are suggestive of photodesorption of organic ices from the surfaces of dust grains, while the sequence of increasing radius of peak intensity represented by DCN (smallest), DCO+, N2H+, and H2CO (largest) is qualitatively consistent with the expected decline of midplane gas temperature with increasing disk radius. Empirical modeling indicates that the sharp-edged C2H emission ring lies at relatively deep disk layers, leaving open the question of the origin of C2H abundance enhancements in evolved disks. This study of the “molecular anatomy” of V4046 Sgr should serve as motivation for additional subarcsecond ALMA molecular line imaging surveys of nearby, evolved protoplanetary disks aimed at addressing major uncertainties in protoplanetary disk physical and chemical structure and molecular production pathways.

Nature, distribution and origin of CO2 on Enceladus

We present the first map of CO2 at the surface of Enceladus using data obtained by the Cassini Visible-Infrared Mapping Spectrometer (VIMS). In order to measure the weak and narrow CO2 absorption band depths around 4.26 µm, we improved: (1) the calibration of VIMS spectra; (2) the calculation of geographic coordinates; and (3) the projection techniques. We averaged multiple observations of a given area to obtain a signal to noise ratio high enough to map the CO2 abundances. CO2 is reliably detected mostly in the South Polar Region. This region includes active faults (Tiger Stripes), the highest observed surface temperatures, and locations of active plume eruptions. The occurrence here of CO2 is consistent with an endogenic origin controlled by tectonics. Both pure CO2 ice and complexed CO2 are detected from the positions of absorption bands between 4.27 and 4.24 µm. The highest concentrations of CO2 are between the main active faults of the South Polar Region, where the surface temperature is low. Pure CO2 ice deposits at the surface of Enceladus are best modeled by the formation of gas pockets below the icy crust and above the surface of the internal ocean. These pockets eventually release cold CO2 gas (∼70 to ∼119 K) at low-velocity (seeping) between the Tiger Stripes [Matson et al., 2018, Icarus, 302, 18–26]. CO2 clathrate hydrates may form in the ocean and may be subsequently released when a CO2 gas pocket blows out and erupts. Other mechanisms may contribute to reinforcing the anti-correlation of the CO2 distribution (of any type) with respect to the location of the Tiger Stripes, such as successive sublimation of CO2 and condensation on colder areas, and partial frost cover by H2O releases from plume eruptions.

Holocene dynamics of the Southern Hemisphere westerly winds and possible links to CO2 outgassing

The Southern Hemisphere westerly winds (SHW) play an important role in regulating the capacity of the Southern Ocean carbon sink. They modulate upwelling of carbon-rich deep water and, with sea ice, determine the ocean surface area available for air–sea gas exchange. Some models indicate that the current strengthening and poleward shift of these winds will weaken the carbon sink. If correct, centennial- to millennial-scale reconstructions of the SHW intensity should be linked with past changes in atmospheric CO2, temperature and sea ice. Here we present a 12,300-year reconstruction of wind strength based on three independent proxies that track inputs of sea-salt aerosols and minerogenic particles accumulating in lake sediments on sub-Antarctic Macquarie Island. Between about 12.1 thousand years ago (ka) and 11.2 ka, and since about 7 ka, the wind intensities were above their long-term mean and corresponded with increasing atmospheric CO2. Conversely, from about 11.2 to 7.2 ka, the wind intensities were below their long-term mean and corresponded with decreasing atmospheric CO2. These observations are consistent with model inferences of enhanced SHW contributing to the long-term outgassing of CO2 from the Southern Ocean. The strength of the Southern Hemisphere westerly winds varied throughout the Holocene, according to a reconstruction from lake sediments, with periods of stronger winds coincident with higher atmospheric CO2 levels.

Air temperature feedback and its contribution to global warming

Air temperature feedback results from the thermal-radiative coupling between the atmosphere and the surface and plays an important role in surface energy balance. This paper reveals the contribution of air temperature feedback to the global warming from 1980 to 2000. The air temperature feedback kernel, evaluated using the ERA-Interim reanalysis data, is used to discuss the physical mechanism for air temperature feedback, the dependency of the strength of air temperature feedback on the climatological spatial distributions of air temperature, water vapor and cloud content, and the contributions of air temperature feedback to rapid global warming. The coupling between temperature feedback and each of the external forcings and individual feedback processes will amplify the anomaly of direct energy flux convergence at the surface induced by the external forcings and individual processes. The air temperature feedback amplifies the initial surface warming due to the increase in CO2 concentration, ice and snow melting, increase in water vapor, and change in ocean heat storage. It also amplifies the surface warming due to the longwave radiaitve forcing associated with the increase in cloud cover, which acts to suppress the cooling of the shortwave effect of cloud forcing. Overall, temperature feedback plays an important role in the global warming from 1980 to 2000, as the net positive contribution to the perturbation of global mean energy flux at the surface from the air temperature feedback is larger than the net negative contribution from external forcing and all non-temperature feedbacks.

Are different Martian gully morphologies due to different processes on the Kaiser dune field?

Abstract We describe and compare the morphology and activity of two types of gullies with different orientations collocated on the Kaiser dune field in the southern hemisphere of Mars: large apron gullies and linear dune gullies. The activity of large apron gullies follows an annual cycle: (i) material collapse into the alcove (mid-autumn/late winter) as CO 2 condenses; (ii) remobilization by mass flows (late winter); and (iii) continuous appearance of hundreds of ‘digitate flows’ on the fan (autumn/winter). We find that large apron gullies could form in hundreds of Martian years. In contrast, linear dune gullies are active briefly in late winter, when the CO 2 frost disappears. Their activity is characterized by the extension of channels, the creation of pits and the darkening of the surface. Linear dune gullies are likely to form within one to tens of Martian years. We infer that insolation, which influences the depth to ground ice and the amount of volatile deposited, may be the factor differentiating large apron gullies and linear dune gullies. Sediment transport by CO 2 sublimation is a good candidate for the activity observed in all of these features. However, linear gullies could also be formed by brine release when the temperature rises abruptly after the removal of the CO 2 ice.

The Effect of Obliquity‐Driven Changes on Paleoclimate Sensitivity During the Late Pleistocene

AbstractWe reanalyze existing paleodata of global mean surface temperature ΔTg and radiative forcing ΔR of CO2 and land ice albedo for the last 800,000 years to show that a state‐dependency in paleoclimate sensitivity S, as previously suggested, is only found if ΔTg is based on reconstructions, and not when ΔTg is based on model simulations. Furthermore, during times of decreasing obliquity (periods of land ice sheet growth and sea level fall) the multimillennial component of reconstructed ΔTg diverges from CO2, while in simulations both variables vary more synchronously, suggesting that the differences during these times are due to relatively low rates of simulated land ice growth and associated cooling. To produce a reconstruction‐based extrapolation of S for the future, we exclude intervals with strong ΔTg‐CO2 divergence and find that S is less state‐dependent, or even constant state‐independent), yielding a mean equilibrium warming of 2–4 K for a doubling of CO2.

Stellar abundance of binary stars: their role in determining the formation location of super-Earths and ice giants

Binary stars form from the same parent molecular cloud and thus have the same chemical composition. Forming planets take building material (solids) away from the surrounding protoplanetary disc. Assuming that the disc's accretion onto the star is the main process that clears the disc, the atmosphere of the star will show abundance reductions caused by the material accreted by the forming planet(s). If planets are only forming around one star of a binary system, the planet formation process can result in abundance differences in wide binary stars, if their natal protoplanetary discs do not interact during planet formation. Abundance differences in the atmospheres of wide binaries hosting giant planets have already been observed and linked to the formation location of giant planets. Here, we model how much building material is taken away for super-Earth planets that form inside/outside of the water ice line as well as ice giants forming inside/outside of the CO ice line. Our model predicts a significant abundance difference $\Delta$[X/H] in the stellar atmospheres of the planet-hosting binary component. Our model predicts that super-Earths that form inside the water ice line ($r<r_{\rm H_2O}$) will result in an $\Delta$[Fe/H]/$\Delta$[O/H] abundance difference in the their host star that is a factor of 2 larger than for super-Earths formed outside the water ice line ($r>r_{\rm H_2O}$) in the water rich parts of the disc. Additionally, our model shows that the $\Delta$[Fe/H]/$\Delta$[C/H] abundance difference in the host star is at least a factor of 3 larger for ice giants formed at $r<r_{\rm CO}$ compared to ice giants formed far out in the protoplanetary disc ($r>r_{\rm CO}$). Future observations of wide binary star systems hosting super-Earths and ice giants could therefore help to constrain the migration pathway of these planets and thus constrain planet formation theories.

Radiolysis of N2O:CO2 ice by heavy ions: simulation of cosmic ray effects

Radiolysis of N2O:CO2 ice by heavy ions: simulation of cosmic ray effects

Ice state evolution during spring in Richardson crater, Mars

The Martian climate is governed by an annual cycle, that results in the condensation of CO2 ice during winter, up to a meter thick at the pole and thousands of kilometers in extension. Water and dust may be trapped during the condensation and freed during the sublimation. In addition, ice may be translucent or granular depending on the deposition process (snow vs direct condensation), annealing efficiency, and dust sinking process. The determination of ice translucency is of particular interest to confirm or reject the cold jet model (also known as Kieffer model).This work is focused on the dune field of Richardson Crater (72° S, 180° W)in which strong interactions between the water, dust and CO2 cycles are observed. We analyzed CRISM hyperspectral images in the near IR using radiative transfer model inversion. We demonstrate that among the states of CO2 ice, the translucent state is observed most frequently. The monitoring of surface characteristics shows a decrease in the thickness of the ice during the spring consistently with climate models simulations. We estimate a very low dust content of a few ppmv into the CO2 ice, consistent with the formation scenario of cold jets. The water impurities is around 0.1%v, almost stable during the spring, suggesting a water escape from the surface of subliming CO2 ice layer. The water ice grain size varies in a range 1 to 50 microns. From these results, we propose the following new mechanism of small water ice grain suspension: as a cold jet occurs, water ice grains of various sizes are lifted from the surface. These jets happen during daytime, when the general upward gas flux from the subliming CO2 ice layer is strong enough to carry the smaller grains, while the bigger fall back on the CO2 ice layer. The smaller water grains are carried away and integrated to the general atmospheric circulation.

Laboratory investigations of the physical state of CO2 ice in a simulated Martian environment

We have experimentally investigated CO2 ice condensation under conditions similar to those expected in the Martian polar areas using the Environmental Wind Tunnel of Aarhus University in the framework of Trans-National Access opportunities within the EuroPlanet Research Infrastructure. Our goal was to condense CO2 directly from the chamber’s atmosphere onto a specially designed cooling plate. We investigated ranges of temperatures and pressures similar to those in Martian polar areas, observed the texture of the created CO2 ice layer, and measured its optical properties. Most importantly, we find that under conditions usual for Martian polar areas in fall and winter, CO2 ice always deposits as a translucent slab. The maximum thickness of the ice that we have achieved approached 2 cm and this CO2 slab ice layer was either transparent or highly translucent. Under significantly lower temperatures or in states away from equilibrium (for example, when CO2 gas input into the chamber was fast and created over-pressure) CO2 deposited as different crystalline structures. In this case, when a thick layer was created, it was not visually transparent. However, even in those cases it still retains some level of translucency. Our results will advance the analysis of remote-sensing data related to CO2 ice, Mars’ seasonal cycles, and various models considering CO2 ice condensation-sublimation related processes.

A search for polycyclic aromatic hydrocarbons over the Martian South Polar Residual Cap

We present our research on compositional mapping of the Martian South Polar Residual Cap (SPRC), especially the detection of organic signatures within the dust content of the ice, based on hyperspectral data analysis. The SPRC is the main region of interest for this investigation, because of the unique CO2 ice sublimation features that cover the surface. These flat floored, circular depressions are highly dynamic, and we infer frequently expose dust particles previously trapped within the ice during the wintertime. Here we identify suitable regions for potential dust exposure on the SPRC, and utilise data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board NASA's Mars Reconnaissance Orbiter (MRO) satellite to examine infrared spectra of dark regions assumed to be composed mainly of dust particles to establish their mineral composition, to eliminate the effects of ices on sub-pixel dusty features, and to look for signatures indicative of Polycyclic Aromatic Hydrocarbons (PAHs). Spectral mapping has identified compositional differences between depression rims and the majority of the SPRC and CRISM spectra have been corrected to minimise the influence of CO2 ice. Whilst no conclusive evidence for PAHs has been found within the detectability limits of the CRISM instrument, depression rims are shown to have higher water content than regions of featureless ice, and there are possible indications of magnesium carbonate within the dark, dusty regions.

The Penetration of Solar Radiation Into Carbon Dioxide Ice

AbstractIcy surfaces behave differently to rocky or regolith‐covered surfaces in response to irradiation. A key factor is the ability of visible light to penetrate partially into the subsurface. This results in the solid‐state greenhouse effect, as ices can be transparent or translucent to visible and shorter wavelengths, while opaque in the infrared. This can lead to significant differences in shallow subsurface temperature profiles when compared to rocky surfaces. Of particular significance for modeling the solid‐state greenhouse effect is the e‐folding scale, otherwise known as the absorption scale length, or penetration depth, of the ice. While there have been measurements for water ice and snow, pure and with mixtures, to date, there have been no such measurements published for carbon dioxide ice. After an extensive series of measurements we are able to constrain the e‐folding scale of CO2 ice for the cumulative wavelength range 300 to 1,100 nm, which is a vital parameter in heat transfer models for the Martian surface, enabling us to better understand surface‐atmosphere interactions at Mars' polar caps.

EVALUASI PELAKSANAAN INSPEKSI APD DI H2, CO2 DAN DRY ICE PLANT DI PT. X KAWASAN GRESIK

Hazards are potentially harmful. In the gas industry that has raw materials, tools / machinery, production and hazardous environment must use the completely and correctly. The purpose of this study is to evaluate the implementation of safety inspection and compliance with the use of PPE in H2, CO2 and dry ice plant in PT. X Region Gresik.This research is descriptive observational research, using cross sectional research design. The sample was 6 workers as sample interview and observation and 1 (one) HSE officer as sample of interview. The data collection includes safety inspection and the compliance of plant workers in the use of PPE. The data analysis used in this research is presented in tabular and narrative form, then using cross tabulation to see whether there is a correlation between the conformity of the number of PPE, the condition of PPE to the worker compliance in the use of PPE.The results showed that majority workers did not use PPE, the number of is not suitable with the number of workers, the condition of PPE is not feasible and compliance of the use of PPE plant workers is still low. Significant linkage between the availability of PPE TO compliance with the use of and the lack of significant correlation between the condition of PPE to the compliance of usage.The conclusion of this research is low frequency of safety inspection. Should increase frequency of safety inspection. And also HSE officer officer in carrying out safety inspection. The suggestion is to increase the compliance of workers in the use of PPE. Keywords: Safety inspection , PPE.

Detection of HOCO+ in the protostar IRAS 16293−2422

The protonated form of CO2, HOCO+, is assumed to be an indirect tracer of CO2 in the millimeter/submillimeter regime since CO2 lacks a permanent dipole moment. Here, we report the detection of two rotational emission lines (4 0,4-3 0,3) and (5 0,5-4 0,4) of HOCO+ in IRAS 16293-2422. For our observations, we have used EMIR heterodyne 3 mm receiver of the IRAM 30m telescope. The observed abundance of HOCO+ is compared with the simulations using the 3-phase NAUTILUS chemical model. Implications of the measured abundances of HOCO+ to study the chemistry of CO2 ices using JWST-MIRI and NIRSpec are discussed as well.

CO 2 sublimation in Martian gullies: laboratory experiments at varied slope angle and regolith grain sizes

Abstract Martian gullies were initially hypothesized to be carved by liquid water, due to their resemblance to gullies on Earth. Recent observations have highlighted significant sediment transport events occurring in Martian gullies at times and places where CO 2 ice should be actively sublimating. Here we explore the role of CO 2 sublimation in mobilizing sediment through laboratory simulation. In our previous experimental work, we reported the first observations of sediment slope movement triggered by the sublimation of CO 2 frost. We used a Mars regolith simulant near the angle of repose. The current study extends our previous work by including two additional substrates, fine and coarse sand, and by testing slope angles down to 10°. We find that the Mars regolith simulant is active down to 17°, the fine sand is active only near the angle of repose and the coarse sand shows negligible movement. Using an analytical model, we show that under Martian gravity motion should be possible at even lower slope angles. We conclude that these mass-wasting processes could be involved in shaping Martian gullies at the present day and intriguingly the newly reported CO 2 -creep process could provide an alternative explanation for putative solifluction lobes on Mars.

Modeling CO, CO2, and H2O Ice Abundances in the Envelopes of Young Stellar Objects in the Magellanic Clouds

Abstract Massive young stellar objects (MYSOs) in the Magellanic Clouds show infrared absorption features corresponding to significant abundances of CO, CO2, and H2O ice along the line of sight, with the relative abundances of these ices differing between the Magellanic Clouds and the Milky Way. CO ice is not detected toward sources in the Small Magellanic Cloud, and upper limits put its relative abundance well below sources in the Large Magellanic Cloud and the Milky Way. We use our gas-grain chemical code MAGICKAL, with multiple grain sizes and grain temperatures, and further expand it with a treatment for increased interstellar radiation field intensity to model the elevated dust temperatures observed in the MCs. We also adjust the elemental abundances used in the chemical models, guided by observations of H ii regions in these metal-poor satellite galaxies. With a grid of models, we are able to reproduce the relative ice fractions observed in MC MYSOs, indicating that metal depletion and elevated grain temperature are important drivers of the MYSO envelope ice composition. Magellanic Cloud elemental abundances have a subgalactic C/O ratio, increasing H2O ice abundances relative to the other ices; elevated grain temperatures favor CO2 production over H2O and CO. The observed shortfall in CO in the Small Magellanic Cloud can be explained by a combination of reduced carbon abundance and increased grain temperatures. The models indicate that a large variation in radiation field strength is required to match the range of observed LMC abundances. CH3OH abundance is found to be enhanced in low-metallicity models, providing seed material for complex organic molecule formation in the Magellanic Clouds.