organic chemistry Archives

Polarization degree (Pr) and polarization position angle (θr) of 3I/ATLAS as a function of phase angle, measured in five bands (RC, IC, J, H, and Ks). Colored symbols denote our visible and near-infrared imaging polarimetric data obtained with different instruments, while orange symbols show previously published measurements of 3I/ATLAS (Z. Gray et al. 2025; M. Zheltobryukhov et al. 2025). Gray symbols represent polarimetric measurements of Solar System comets compiled in the Database of Comet Polarimetry (DBCP; N. Kiselev et al. 2017), and the pink triangles indicate the PPC of the interstellar comet 2I/Borisov (S. Bagnulo et al. 2021). The dashed curves show the best-fit linear–exponential models (Equation 1) to our data. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

Dust Properties of the Interstellar Object 3I/ATLAS Revealed by Optical and Near-Infrared Polarimetry

by Keith CowingJanuary 15, 2026January 15, 2026

We present independent polarimetric observations of the interstellar object 3I/ATLAS, including the first near-infrared polarimetric measurements. Using imaging polarimeters, we measured the degree of linear polarization from the visible RC […]

A color–magnitude Hess diagram of Sextans A with JWST/ NIRCam photometry at 2.7 and 4.4 μm with the positions of the JWST/LRS targets overplotted. COLIBRI isochrones with [M/H] = −1.7 are plotted for log(age) = 8.3 in orange and log(age) = 9 in blue (P. Marigo et al. 2013), both showing prominent branches of thermally pulsing AGB stars at red colors (F277W − F444W > 0 mag). The population of faint red objects is dominated by unresolved background galaxies and young stellar objects (J. T. Warfield et al. 2023; L. Lenkić et al. 2024). -- astro-ph.GA

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

JWST Captures Growth of Aromatic Hydrocarbon Dust Particles in the Extremely Metal-poor Galaxy Sextans A

by Keith CowingJanuary 13, 2026January 13, 2026

The mid-infrared spectrum of star-forming, high metallicity galaxies is dominated by emission features from aromatic and aliphatic bonds in small carbonaceous dust grains, often referred to as polycyclic aromatic hydrocarbons […]

The sketch of the protostellar core adopted in this model, including a central source characterised by the bolometric luminosity (L∗) and the stellar temperature (T∗). The inner zone is characterised by the sublimation threshold of dust grains (Tsub) and the threshold radius (rthreshold). The thin shell of hot dust is determined by the shell temperature (Tshell) and its radius (Rshell). The outer region is given by the outer radius (rout). -- astro-ph.GA

Astrochemistry, Biochemistry & Organic Chemistry, Imaging & Spectroscopy, Interstellar, Press Release

One-dimensional And Time-dependent Modelling Of Complex Organic Molecules In Protostars

by Keith CowingJanuary 6, 2026January 6, 2026

Complex organic molecules (COMs), the building blocks of life, have been extensively detected under various physical conditions, from quiescent clouds to star-forming regions.

Graphic of the proposed scenario of sublimation in a disk with a warm dust trap, viewed from the side, based on van der Marel et al. (2021b). If the bulk of the dust content is located in a dust trap inside the CO snowline at 30 K, this implies that fragments of its icy pebbles can be transported vertically to the higher disk layers above the H2O snow surface at 150 K, and sublimate their icy content into the gasphase, where it becomes observable. If the bulk of the pebbles is located outside the CO snowline, its icy layers may remain frozen out and its contents are not revealed in the gas phase. Such a scenario may also apply to PAHs, which is the hypothesis of this work. -- astro-ph.EP

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

Observational Evidence For A Possible Link Between PAH Emission And Dust Trap Locations In Protoplanetary Disks

by Keith CowingDecember 30, 2025December 30, 2025

Polycyclic Aromatic Hydrocarbons (PAHs) are commonly detected in protoplanetary disks, but it is unclear what causes the wide range of intensities across the samples.

This NASA/ESA Hubble Space Telescope image features a section of the Tarantula Nebula in the Large Magellanic Cloud. ESA/Hubble, NASA, and C. Murray larger image

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Interstellar, Status Report

Redox Diversity of Interstellar Compounds and Human Nutrients Reveals a Potentially Universal Chemical Constraint for Life

by Keith CowingDecember 30, 2025December 30, 2025

Comparative analysis of redox properties across three chemically distinct datasets—interstellar compounds, human nutritional molecules, and >40 million substances in the PubChem database—reveals a striking and highly non-random pattern.

Combined white light image of 3I/ATLAS, created by median stacking white light images produced by collapsing in wavelength individual data cubes. The field of view displayed is 40 arcsec x 40 arcsec . Intensities are in units of 10-20 ergs−1 cm−2. Countours are over plotted. Snapshot of a new interstellar comet: 3I/ATLAS has a red and featureless spectrum, MRAS

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Press Release

University Of Canterbury Team Led Study Of Interstellar Comet 3I/ATLAS

by Keith CowingDecember 30, 2025December 30, 2025

The comet 3I/ATLAS, discovered by an international team in July this year, is only the third interstellar object ever found in the history of astronomy. It is the first that […]

Dust clouds reflect starlight around the star R Doradus. As it nears the end of its life, the star is shedding its outer layers, forming clouds of gas and dust around it (shown here in pink and yellow). Scientists have long believed that starlight illuminating these clouds could power a stellar wind. But the colour of the light around the star reflected by dust, , shows that the dust grains are too small to explain the star’s wind. The image was taken in polarised visible light with VLT/SPHERE. In the centre in yellow and orange, we see ALMA’s image showing the surface of the star. Credit ESO/T. Schirmer/T. Khouri; ALMA (ESO/NAOJ/NRAO)

Astrochemistry, Biochemistry & Organic Chemistry, Biophysics, Interstellar, Panspermia, Press Release, Space Weather & Heliophysics

Stardust Study Resets How Life’s Atoms Spread Through Space

by Keith CowingDecember 29, 2025December 29, 2025

Starlight and stardust are not enough to drive the powerful winds of giant stars, transporting the building blocks of life through our galaxy. That’s the conclusion of a new study […]

A)–(D). Spectrally integrated flux maps for HCN, CO, CH3OH, and CS in K2. Contour intervals in each map are given in multiples of the rms noise. The rms noise (σ, mJy beam−1 km s−1 ) is indicated in the upper left corner of each panel. Sizes and orientations of the synthesized beam (Table 1) are indicated in the lower left corner of each panel. The comet’s observer-centered illumination (ϕ ∼ 25◦ ), as well as the direction of the Sun and dust trail, are indicated in the lower right. The black cross indicates the position of the peak continuum flux. A spectrum extracted from a 10′′ diameter aperture centered on the nucleus is shown in the upper right. Contours are in 10σ increments for HCN and 5σ increments for CO, CH3OH, and CS. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

The Evolution in Coma Molecular Composition of Comet C/2017 K2 (PanSTARRS) Across the H2O Sublimation Zone: ALMA Imaging of an H2O-Dominated Coma

by Keith CowingDecember 29, 2025December 29, 2025

We report a survey of molecular emission from cometary volatiles using the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2017 K2 (PanSTARRS) carried out on UT 2022 September 21, 22, […]

Optical image of comet C/2025 A6 obtained on 21st October 2025 (18:35–18:50, UTC+8) with the 70-cm UCASST telescope. The image combines 5-min exposures in each of the R, V, and B filters and shows a coma with an apparent diameter of ∼8–10 arcmin. The telescope is equipped with a 2048×2048 detector with a pixel size of 13.5 µm, providing a field of view of about 20.8'×20.8', at the time of the observation, 1′ corresponds to a projected scale of ∼25,700 km at the comet. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

From Emission To Absorption: The FAST Observation Of The OH 18-cm Lines From The Comet C2025/A6

by Keith CowingDecember 29, 2025December 29, 2025

We observed comet C/2025 A6 with FAST telescope equipped with the ultra-wideband receiver from 23rd October to 8th November 2025 and detected the OH 18-cm lines for the first time.

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Fossils & Paleontology, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Status Report

Designing Peptide Fossils That Model the Evolution of the Bacterial Ferredoxin Fold

by Keith CowingDecember 29, 2025December 29, 2025

Electron transfer coupled to redox chemistry is at the heart of metabolism. The proteins responsible for moving electrons (protein electron carriers) must have emerged at the origin of life.

organic chemistry

Dust Properties of the Interstellar Object 3I/ATLAS Revealed by Optical and Near-Infrared Polarimetry

JWST Captures Growth of Aromatic Hydrocarbon Dust Particles in the Extremely Metal-poor Galaxy Sextans A

One-dimensional And Time-dependent Modelling Of Complex Organic Molecules In Protostars

Observational Evidence For A Possible Link Between PAH Emission And Dust Trap Locations In Protoplanetary Disks

Redox Diversity of Interstellar Compounds and Human Nutrients Reveals a Potentially Universal Chemical Constraint for Life

University Of Canterbury Team Led Study Of Interstellar Comet 3I/ATLAS

Stardust Study Resets How Life’s Atoms Spread Through Space

The Evolution in Coma Molecular Composition of Comet C/2017 K2 (PanSTARRS) Across the H2O Sublimation Zone: ALMA Imaging of an H2O-Dominated Coma

From Emission To Absorption: The FAST Observation Of The OH 18-cm Lines From The Comet C2025/A6

Designing Peptide Fossils That Model the Evolution of the Bacterial Ferredoxin Fold

Isobaric Crystallization of Aqueous Magnesium Chloride Solutions at Icy Moon Conditions

Systematic Uncertainties in Rocky Exoplanet Reflected Light from Incomplete Laboratory BRDF Measurements

New Discovery Links Hemispheres In The Mystery Of Earth’s Past Ice Ages

UV Photodamage Pathways And The Evolutionary Selection Of Thymine Over Uracil In Early Genetic Systems

Reversion To The Meta Body Form Of Life After Complete Cell Death In Pure Liquid Water