![Effect of substrate morphology and composition on the UV photodesorption of water ice at 12 K. (A) Evolution of the XPS-derived ice coverage as a function of photon fluence for an initial coverage of approximately 4 ML deposited on planar gold, planar olivine crystal, olivine microparticle powder, and soot at 12 K. Linear fits to the coverage curves give photodesorption yields of 1.5 × 10−3 , 1.8 × 10−3 , 7.2 × 10−4 , and 7.2 × 10−5 molecule photon−1 , respectively (see Table 1). (B) Scanning electron microscopy image of the olivine powder film, showing micrometer- and submicrometer-sized angular particles. (C) Scanning electron microscopy image of the soot film, showing highly aggregated carbon nanoparticles with a much finer and more ramified morphology. (D) Coverage derived from XPS measurements as a function of UV fluence at 12 K for 2 ML ice films deposited at 120 K (nonporous ice) and 12 K (porous ice), giving photodesorption yields of 4.6 × 10−5 and 1.4 × 10−5 molecule photon−1 , respectively -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/11/Suppression.png?resize=1200%2C720&ssl=1)
[astro-ph.IM] Ultraviolet (UV) photodesorption regulates the partitioning of water between interstellar ice mantles and the gas phase, yet laboratory yields are generally measured on planar substrates rather than on surfaces […]
interstellar ice
Posted inAstrochemistry
Pre-Accretion Formation of Sulfuric Acid in Interstellar Ice Analogs: Implications for Sulfate in Ryugu and Bennu
[The Journal of Physical Chemistry Letters] Sulfate-bearing phases and soluble sulfate species, including sodium sulfate (Na2SO4), in carbonaceous asteroids are commonly attributed to parent-body aqueous alteration, yet the formation of […]
![Infrared spectra of pure H2S (blue) and H2O:H2S (10:1) (red) ice mixtures after UV irradiation followed by warm-up to room temperature, measured at 300 K. The residue from the H2S ice does not show any IR absorption band. Functional groups assigned to bands in the H2O:H2S (10:1) residue are indicated at the top; vibrational bands and assignments are also listed in Table 1, along with possible carrier species or chemical families producing those features. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Water-.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Water Enhances The Formation Of Refractory Sulfur In Interstellar Ices
[astro-ph.GA] Sulfur is the tenth most abundant element in space, yet it is strongly depleted in the gas phase of dense interstellar regions, suggesting sequestration in dust grain components that […]
Posted inAstrochemistry
Secondary Ion-Ice Chemistry in UV-Irradiated Oxygen Ice: New Astrochemical Models Including Bulk Ionic Species
[ACS Earth Space Chemistry] Although energetic and nonenergetic processing of interstellar dust grain surfaces and ice is thought to be one of the dominant mechanisms for the extraterrestrial synthesis of […]
![Visual abstract -- [Journal of the American Chemical Society]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Nonequilibrium.jpg?resize=1200%2C716&ssl=1)
Posted inAstrochemistry
Nonequilibrium Formation of Pyridine (C5H5N) in Interstellar Ice Analogs: Implications for Biorelevant Nitrogen Heterocycles in Ryugu and Bennu
[Journal of the American Chemical Society] Biorelevant nitrogen heterocycles, including the five canonical nucleobases found in RNA and DNA, have recently been identified in samples returned from the carbonaceous asteroids […]
![Observed spectra compared to laboratory data for CO (left), 13CO2 (middle), and H2O (right) ices on carbonaceous dust analogs. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Molecule-specific.png?resize=1200%2C606&ssl=1)
Posted inAstrochemistry
Molecule-specific Diffusion And Desorption Of Interstellar Ices On Carbonaceous Dust
[astro-ph.GA] Interstellar ices form on dust grains in the coldest regions of molecular clouds and preserve key volatile reservoirs that could be incorporated into protoplanetary disks during star and planet […]
![Microscopic Image of Organic Ice Mixture captured from the O-PTIR high resolution microscope. -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Detection-of-Organics.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Detection of Organics in Water Ice by Optical-PhotoThermal Infrared Spectroscopy
[astro-ph.IM] The detection and characterization of organic molecules within water ice is vital for interpreting observations of icy moons and comets. However, organic-ice interactions often distort intrinsic water-ice absorption features, […]
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report
The First Glimpse of Water Ice Absorption Map in the Milky Way
Interstellar ice plays a key role in the thermal evolution of the interstellar medium and in astrochemical pathways, yet its large-scale distribution remains poorly constrained.
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Intelligence & Language, Press Release
SPHEREx Wide-Field Infrared Spectral Mapping of Interstellar Ices and Polycyclic Aromatic Hydrocarbons
We present some of the first infrared spectral maps acquired by SPHEREx. These maps, which to our knowledge are the largest of their type ever compiled in the near-infrared, reveal […]
Posted inAnalog Studies, Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Status Report
Experimental And Computational Studies Of The Hydrogenation Of Carbon Disulfide (CS2) On Ice Analogues
Carbon disulfide (CS2) is one of the sulfur-bearing species expected to be present in the interstellar medium (ISM). In this study, we investigated the surface reactions of solid CS2 with […]