ices Archives

Abundances (w.r.t. H nuclei) of main C and O carriers in the baseline and full chemistry models without transport. C species represent the combination of all species containing carbon, but not oxygen; O species represent the species containing oxygen, but not carbon; C+O species represent the species containing both carbon and oxygen. From all the grouped species, the initially present H2O, CO2 , CO and CH4 are excluded. Solid lines represent ice-phase species, and dashed lines represent gas-phase species. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Metamorphoses Of Carbon And Oxygen In Protoplanetary Discs: How Chemistry And Radial Drift Transform Inner Disc C/O Ratios

by Keith CowingJune 2, 2026June 2, 2026

The chemical composition of a protoplanetary disc is sensitive to its thermal structure and dust properties, and can provide insights into the disc evolution.

Representative adsorption geometries for HCSCN (panels a–c) and HCSCCH (panels d–f) on the TIP4P (𝐻2𝑂)10 cluster at the 𝜔B97XD/def2-TZVP level of theory, illustrating the three structurally distinct binding topologies sampled across the full 𝑛 = 6–16 survey. Atom colours: O (red), H (white), C (tan), N (blue), S (yellow); cyan distances mark resolved intermolecular hydrogen-bond contacts. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Ice as a Photochemical Shield: Adsorption Energetics and Spectroscopic Modulation of Interstellar Thiocyanates HCSCN and HCSCCH in TMC-1

by Keith CowingApril 22, 2026April 22, 2026

The recent detections of thioformyl cyanide (HCSCN) and propynethial (HCSCCH) in TMC-1 provide critical insights into the interstellar sulfur inventory, yet their sequestration and survivability on dust grain mantles remain […]

A three-color image of the CygX region constructed from SPHEREx mosaics. In this image, blue is 1.13–1.19 μm, green is 2.9–3.20 μm (containing the H2O ice absorption feature), and red is 4.75–5.1 μm. Continuum emission from warm dust extends across the image, as evidenced by the extended orange clouds. Dark lanes are seen where the dust and H2O ice absorption are the strongest. Red sources appear in these dark lanes where there are background sources or embedded young stars shining through the dust. Blue stars are seen in regions with lower extinction or are foreground objects. -- The Astrophysical Journal

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release

Astrochemistry Update: SPHEREx Maps Vast Galactic Ice Regions

by Keith CowingApril 15, 2026April 15, 2026

NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) mission has mapped interstellar ice at an unprecedented scale.

Geometries of the H-addition reactions on HNC leading to cis- and trans-HC•NH (reactions R4-cis and R4-trans). Distances are in Å -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Methanimine As A Sink In The HCN And HNC Solid State Hydrogenation Network

by Keith CowingApril 13, 2026April 13, 2026

We aim to provide a systematic and quantitative description of the hydrogenation network connecting HCN and HNC to methylamine on interstellar water ices, while identifying dominant pathways and bottlenecks.

Dust surface density evolution in the fiducial model without disk buildup (left) and with disk buildup taken into account (right). Time zero refers to the moment the gas disk reaches maximum mass in the model including its buildup, corresponding to the time the dust is initialized in the model without disk buildup. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report

Dust Evolution During Protoplanetary Disk Bbuildup Enhances CO Ice Relative To Water

by Keith CowingApril 1, 2026April 1, 2026

Water ice is expected to be the dominant volatile component of bodies formed in the outer Solar System. However, recent observations of comets and trans-Neptunian objects suggest that the relative […]

[Top] The boulder-covered moon Dimorphos as seen 8.55 seconds before the impact of the DART space craft. [Bottom] The same image after correcting for lighting conditions across the surface and shadows cast by boulders, revealing a fan-shaped pattern of streaks (highlighted in color for emphasis). Credit: NASA/JHU-APL/UMD.

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Meteorites & Asteroids, Missions & Hardware, Panspermia, Press Release, Sample Return

New NASA DART Mission Data Reveals that Asteroids Throw ‘Cosmic Snowballs’ at Each Other

by Keith CowingMarch 11, 2026March 11, 2026

About 15% of asteroids near Earth have small moons orbiting them, making binary asteroid systems common in our cosmic neighborhood.

Simulation results of abundance ratios [H2O2]/[H2O] (black lines), [H2]/[H2O] (orange lines), and [O2]/[H2O] (blue lines) with our model (model A) at 16 K (solid lines) and 77 K (dashed lines). The gray shaded and line filled regions show the experimental results of [H2O2]/[H2O] by Gomis et al. (2004a) at 16 and 77 K, respectively, with an assumed uncertainty of a factor of 3. -- astro-ph.GA

AI - Data - Apps - Cybernetics, Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Simulation Of Proton Radiolysis Of H2O And O2 Ices With The Nautilus Code

by Keith CowingFebruary 25, 2026February 25, 2026

The radiolysis effect of cosmic rays (CRs) plays an important role in the chemistry in molecular clouds. CRs can dissociate the molecules on dust grains, producing reactive suprathermal species and […]

D/H ratios for CH2DOH (left panel) and CH3OD (right panel) across the star-forming sequence. The spread per source type was calculated using all column densities listed in Table A. The black circle denotes the average of the values. The values of CH2DOH have been statistically corrected. Violin plots demonstrate the density distribution of the data: the wider the area of the violin, the more data points are around this value; narrow regions show that data are sparse at this value. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

First Detection Of CH3OD In Prestellar Cores

by Keith CowingNovember 10, 2025November 10, 2025

The isotopic ratios of deuterated methanol derived around protostars are commonly used to infer the physical conditions under which they formed in the earlier prestellar stage.

Abundances (top) and correlation coefficients (bottom) of H2O, CO, CO2, CH3OH, and NH3 ices at T = 10 K, nH/ = 105 cm−3, ζ = 1.3 × 10−17s−1 and FUV = 1 Habing. In top panels, the dashed pink line indicates the abundance using the nominal network, black lines indicate the individual samples, and light green is the log-average of all samples. In bottom subplots, the dashed gray line indicates perfectly uncorrelated parameters (rRIN = 0), and the filled gray area indicates “weakly” correlated parameters (|rRIN| < 0.4). The colored filled areas correspond to the 95% confidence intervals of the correlation coefficients. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

A Sensitivity Analysis Of Interstellar Ice Chemistry In Astrochemical Models

by Keith CowingNovember 9, 2025November 9, 2025

Astrochemical models are essential to bridge the gap between the timescales of reactions, experiments, and observations.

Photodestruction cross sections of ethanol in pure and mixed ice samples (1 Mb = 10−18 cm2 ). (a) Results are plotted versus the mixing ratio with CO. The black data markers correspond to Series 1, wherein the initial column density of ethanol is fixed at around 2 × 1016 cm−2 , and the mixing ratio and total initial thickness vary. The blue line shows the fit summarized in Eq. 29. (b) Results are plotted for data series where the fractional composition of the initial ice mixture is held constant and the total thickness is varied. -- astro-ph.GA

Analog Studies, Astrochemistry, Biochemistry & Organic Chemistry, Biophysics, Imaging & Spectroscopy, Interstellar, Status Report

UV Irradiation Of Ethanol-containing Interstellar Ice Analogs: Photostability In CH3CH2OH:CO Mixtures

by Keith CowingNovember 5, 2025

Ethanol (CH3CH2OH) has been detected in interstellar ices within regions associated with the early stages of star and planet formation.

ices

Metamorphoses Of Carbon And Oxygen In Protoplanetary Discs: How Chemistry And Radial Drift Transform Inner Disc C/O Ratios

Ice as a Photochemical Shield: Adsorption Energetics and Spectroscopic Modulation of Interstellar Thiocyanates HCSCN and HCSCCH in TMC-1

Astrochemistry Update: SPHEREx Maps Vast Galactic Ice Regions

Methanimine As A Sink In The HCN And HNC Solid State Hydrogenation Network

Dust Evolution During Protoplanetary Disk Bbuildup Enhances CO Ice Relative To Water

New NASA DART Mission Data Reveals that Asteroids Throw ‘Cosmic Snowballs’ at Each Other

Simulation Of Proton Radiolysis Of H2O And O2 Ices With The Nautilus Code

First Detection Of CH3OD In Prestellar Cores

A Sensitivity Analysis Of Interstellar Ice Chemistry In Astrochemical Models

UV Irradiation Of Ethanol-containing Interstellar Ice Analogs: Photostability In CH3CH2OH:CO Mixtures

NASA Spaceline Current Awareness List #1,206 2 July 2026 (Space Life Science Research Results)

Older Than The Sun: Astronomers Find New Clues To The Origin Of Interstellar Comet 3I/ATLAS

Carl Sagan Month: Call For Participation

The Habitable Worlds Observatory Technology Development Plan

Searching For The Elusive CH2+ With The James Webb Space Telescope. Another Carbocation To Constrain Astrochemical Networks