astro-ph.GA] Archives - Astrobiology

Fig. 9: Distribution of water ice. The color map represents the smoothed Aice W1 values, where blue indicates the existence of water ice absorption. Several well-known regions are enclosed in boxes and labeled as regions 1 to 5, they are (1)Orion-Taurus-Perseus (OTP) region, (2)Cygnus Complex, (3)Serpens region, (4)Ophiuchus region and (5)Vela Co -- astro-ph.GA

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

The First Glimpse of Water Ice Absorption Map in the Milky Way

by Keith CowingJune 3, 2026June 3, 2026

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.

TMC-1 (detail) ESA/Herschel/NASA/JPL-Caltech; acknowledgement: R. Hurt (JPL-Caltech), CC BY-SA IGO 3.0 Source

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

The Impact Of Hydrogen Atom Tunneling On Aromatic Chemistry In TMC-1

by Keith CowingApril 24, 2026April 24, 2026

Hydrogen atom tunneling likely plays a substantial role in the gas-phase chemistry of astrochemical environments. To determine the potential effect that it has on the chemical modeling of aromatic molecules, […]

Molecular structures of cis-HCOOH and transHCOOH. Carbon (C), hydrogen (H), and oxygen (O) atoms are represented by grey, white, and red spheres, respectively -- astro-ph.GA

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

Organic Acid Chemistry in ISM: Detection of Formic Acid and its Prebiotic Chemistry in Hot Core G358.93−0.03 MM1

by Keith CowingFebruary 12, 2026June 10, 2026

In the interstellar medium, formic acid (HCOOH) plays a significant role in the synthesis of the simplest amino acid, glycine (NH2CH2COOH). The presence of HCOOH suggests that oxygen-bearing molecules may […]

Modeled time-dependent carbon fractions of every carbon-containing species in the network with a C/O ratio of 0.5. Each dot represents a species that contains carbon plotted according to its UMAP vectors. The color corresponds to the elemental composition, while the size is the fraction of carbon multiplied by a scaling factor. Molecular structures are shown for species comprising at least 2% of the total carbon. Some of structures are slightly offset from their corresponding dots for visual clarity. Structures for ice-phase (grain surface or mantle) species are highlighted in green. -- astro-ph.GA

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

Modeling The Effect Of C/O Ratio On Complex Carbon Chemistry In Cold Molecular Clouds

by Keith CowingJanuary 14, 2026January 14, 2026

Elemental abundances, which are often depleted with respect to the solar values, are important input parameters for kinetic models of interstellar chemistry. In particular, the amount of carbon relative to […]

ETI broadcasts of a galaxy over its history form a population described by distributions (left). Surveys, and observations within the surveys, select subsets of the positions, times, and frequencies (and polarizations, not shown) spanned by this population, drawing samples treated as random sets (middle). In turn, measurement yields observable quantities, which are themselves random variables with probability distributions dependent on the sample drawn by the observation (right). Both the sampling itself and the measurement conditionalized on the observed sample contribute variance to the final quantity. -- astro-ph.GA

Astronomy & Telescopes, Biosignatures & Paleobiology, Intelligence & Language, SETI & Technosignatures, Status Report

Artificial Broadcasts as Galactic Populations: I. A Point Process Formalism for Extraterrestrial Intelligences and Their Broadcasts

by Keith CowingOctober 7, 2025October 7, 2025

Artificial broadcasts from extraterrestrial intelligences (ETIs) are a hypothetical class of celestial phenomena.

Efficiency factors of crystalline ice grains with carbon inclusions for grain radii of 1 (red), 2 (blue), 5 (green), and 10 µm (brown). The inclusion fraction is set as 0.1. (a) The solid lines indicate the extinction efficiency factors in the 3 µm region. The scattering and absorption efficiency factors for a 2 µm grain are also shown with the dotted and dashed lines. (b) Absorption efficiency factors in the FIR. The colors are the same as in (a). -- astro-ph.EP

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

Searching For Missing Interstellar Oxygen In The Far-infrared

by Keith CowingSeptember 3, 2025

Study of interstellar elemental depletion poses an important problem in the interstellar matter that at least a quarter of the total oxygen (∼160 ppm relative to hydrogen) is not accounted […]

LEFT: Predicted 22Ne mass fraction as a function of metallicity for the WD remnants of stars in the Hypatia Catalog (Hinkel et al. 2014). The colors represent [N/H] for the same stars. MIDDLE and RIGHT: C and N abundances of the same stars from the Hypatia Catalog. The color bars represent the predicted neon mass fraction, X(22Ne), in their remnants. Two chemically peculiar low-metallicity objects, BD+80 245 and HD 19445, are labeled and marked as stars. -- astro-ph.SR

Astronomy & Telescopes, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

The Fraction Of Distilled White Dwarfs With Long-Lived Habitable Zones

by Keith CowingAugust 19, 2025

After carbon and oxygen, 22Ne is the most abundant element in white dwarf interiors. As C/O white dwarfs (WDs) crystallize, they are predicted to go through a distillation process in […]

Deepstacked images of 3I/ATLAS in the TESS FFIs. We present two images per each camera/CCD pairing. 3I/ATLAS is centered in each image and is highlighted with a red circle. We stack all available FFIs for Camera 2 CCD 3. We limit the stacked images for Camera 1 CCD 2 to cutouts which are not overcrowded with bright sources. Due to the large pixel scale of TESS (bottom left), we are unable to resolve any astrometric information from the images. -- astro-ph.EP

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

Precovery Observations of 3I/ATLAS from TESS Suggests Possible Distant Activity

by Keith CowingJuly 31, 2025July 31, 2025

3I/ATLAS is the third macroscopic interstellar object detected traversing the Solar System. Since its initial discovery on UT 01 July 2025, hundreds of hours on a range of observational facilities […]

Example of a simulated SO3 amorphous ice with 8 molecules in a cubic box with periodic boundary conditions. -- astro-ph.GA

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

Photodesorption Of SO2 And SO From UV-irradiated SO2 Ices

by Keith CowingJuly 13, 2025July 13, 2025

The detection of high gas-phase abundances of SO2 and SO in the cold envelope of an intermediate mass protostar suggests that these molecules might form on icy dust grains and […]

Distance vs. Stellar Mass for over 15,000 known galaxies out to 50 Mpc (Ohlson et al. 2024). Galaxies are colorcoded by their Hubble “T” Type, with early type galaxies T < 0 and late-type galaxies T > 0. The three stellar luminosity depth limits – RGB, sub-Red Clump, and sub-oMSTO – are shown as lines, corresponding to the distances where they are achievable for massive galaxies, and color-coded according to Fig. 1. The distances for these 3 depths achievable with HST and JWST are shown as dashed lines, while those achievable with HWO are shown as solid lines. The increase in galaxy diversity accessible from JWST→HWO is striking. The color bimodality of galaxies (e.g., Baldry et al. 2004) is visible within HWO’s reach, as is the Virgo Cluster which is notable as a vertical line of enhanced density. -- astro-ph.GA

Astronomy & Telescopes, Imaging & Spectroscopy, Status Report, Stellar Cartography

Resolving Individual Stars in Nearby Large Galaxies with the Habitable Worlds Observatory

by Keith CowingJuly 5, 2025July 5, 2025

The varied and dynamic evolutionary histories of galaxies give rise to the stunning diversity in their properties that we observe in the present-day universe.