Interstellar Archives

Images of comet 7P/Pons–Winnecke taken during a period of quiescence (left, taken at 2021 July 28 10:25:23 UTC) and the 2021 July 10 outburst (right, taken at 2021 July 10 02:29:58 UTC). The outburst ejecta is apparent as distortions in the observed surface brightness as compared to the ambient coma image. The bottom row shows the logarithmically scaled data with contours spaced every 0.5 mag/arcsec2 . A color bar provides the surface brightness scale. Images are oriented with north up, and east to the left. -⊙ represents the anti-solar direction and V is the heliocentric velocity direction, and a linear scale bar is shown. The blue arrows highlight two linear features as a result of the ejecta distribution that are meeting at a near-right angle in front of the nucleus. -- astro-ph.EP

A Look At Eight Outbursts Of Comet 7P/Pons-Winnecke

by Keith CowingJune 26, 2026June 26, 2026

Cometary outbursts may be used as a means to infer the physical processes occurring on cometary nuclei. To that end, we studied eight outbursts of comet 7P/Pons-Winnecke identified between 2021 […]

Reaction mechanism for the CN + H2CS system computed at the CCSD(T)-F12a+ZPE//DSDPBEP86/aug-cc-pVTZ level. Relative energies are given in kcal mol−1 with respect to the separated reactants. - -astro-ph.GA

Astrochemistry

Reaction Mechanisms and Kinetics of CN and CCH with H2CS: Implications for Interstellar Sulfur Chemistry

by Keith CowingJune 24, 2026June 24, 2026

We report an ab initio and master-equation investigation of the gas-phase reactions of thioformaldehyde (H2CS) with CN and CCH radicals, motivated by the recent detection of the S-containing species HCSCN […]

Interstellar Comet 3I/ATLAS (NIRSpec IFU) -- ESA (larger Image)

Comets and Asteroids

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

by Keith CowingJune 23, 2026June 23, 2026

The third identified interstellar comet in human history has a surprising chemical makeup, raising questions as to how common, or unusual, conditions in our own Solar System may be.

Panels (a)–(o) show contour maps of the observed isophotes (black lines) together with the corresponding modelled isophotes (red lines) for the case 𝑟max = 1 cm. For each of these contour panels, a companion plot is displayed to the right, labelled (a′ )–(o′ ), showing a one-dimensional scan extracted along the direction indicated by the straight red line in the corresponding contour map. In these primed panels, the black and red curves represent the observed and modeled brightness profiles, respectively. The 𝑥- and 𝑦-axes in the contour plots are given in pixel units, and the innermost isophote levels as well as the physical dimensions of each image are listed in Tables 1 and 3. In panels (a)–(o), isophote levels increase outward in steps of 1 mag. In the primed panels, the 𝑥-axis is expressed in pixel units and the 𝑦-axis in surface brightness units (mag arcsec−2). -- astro-ph.EP

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

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

by Keith CowingJune 19, 2026June 19, 2026

We report multi-band photometric imaging observations and Monte Carlo dust tail modelling of the interstellar comet 3I/ATLAS covering a wide range of heliocentric distances, from about 4 au pre-perihelion to […]

Modes of interstellar expansion across two dimensions. The horizontal axis (expansion agent) runs from biological (crewed colonization, settlers, generation ships) to machine (autonomous probes, robotic seed systems). The vertical axis (visibility) runs from quiet (low-mass, low duty cycle, weak technosignatures) to loud (high-power, high waste heat, galaxy-scale signatures). The four quadrants summarize alternative expansion modes considered in the literature; the quiet expansion filter proposed in this paper occupies the lower-right quadrant (highlighted). -- astro-ph.IM

AI - Data - Apps - Cybernetics, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report

Autonomous AI-Cosmoindustry and the Quiet Expansion Filter: A Threshold-Based Resolution of the Fermi Paradox

by Keith CowingJune 16, 2026June 16, 2026

The Fermi paradox is sharpened, not weakened, by plausible extrapolations of artificial intelligence, autonomous robotics, in-situ resource utilization, orbital manufacturing, space-based computing, and uncrewed interstellar probes.

GLS periodograms of individual wavelength contrast lightcurves. In each of the panels, the light pink, dark pink, and black highlighted lines are the 1st, 2nd, and 3rd 12CO bandheads, respectively. The grey horizontal lines indicate the 1%, 5%, and 10% false alarm probabilities. The black vertical lines indicate the expected rotation period at 8.7 hrs and its first integer harmonic at 4.35 hrs. The top panel shows the uncorrected periodogram, with all wavelengths significantly affected by systematic effects caused by the fibre coupling. The middle panel shows the periodogram after the polynomial correction, while the bottom panel adds Gaussian smoothing to this to highlight strong periodic signals. -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Beta Pictoris, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

13CO And Potential Variability In β Pictoris b With GRAVITY+

by Keith CowingJune 14, 2026June 14, 2026

The 12CO/13CO ratio was introduced as an indicator for where in the disk a planet has formed. Previously a lower value compared to the host star’s was suggested to show […]

Carbon isotope ratio as a function of the semi-major axis for young, directly-imaged companions. Measurements in the HR 8799 system for planets e, b, and c (Ruffio et al. 2026) are shown with squares and connected with a dotted line. The other measurements are for HD 984 b (Costes et al. 2024), GQ Lup b (González Picos et al. 2025b), VHS 1256 b (Gandhi et al. 2023), YSES 1 b (Zhang et al. 2024), AB Pic b (Gandhi et al. 2025), and DH Tau b and HIP 79098 b (Xuan et al. 2024a). The present-day local ISM (12C/13C = 68±14; Milam et al. 2005) and solar photospheric value (12C/13C⊙ = 91.4 ± 1.3; Lyons et al. 2018) are overlaid. The horizontal line spans the typical CO snow-line location for a solar-type host star (22–36 au). For stars hotter than the Sun, the CO snow line is expected at distances greater than 30 au, so β Pic b is located interior to the CO snow line. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

The Carbon Isotope Ratio Of β Pic b With High-resolution Spectroscopy

by Keith CowingJune 13, 2026June 13, 2026

Isotopic ratios trace the formation and evolution of planets and link their atmospheres to the chemistry of their natal protoplanetary discs.

Optical depth spectrum and ENIIGMA best-fit model for the 4.0-4.45 µm region and its separate components. Major gas lines are labeled. The inset zooms in on the HDO ice feature. -- astro-ph.EP

Astrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release, Water/Hycean Worlds & Oceanography

First Detection Of HDO Ice In A Protoplanetary Disk

by Keith CowingJune 11, 2026June 11, 2026

Protoplanetary disks are the birthplace of planets and planetary systems. Investigating the molecular inventory of disks is key to linking the chemical evolution of the interstellar medium and the makeup […]

The Wow! signal was a 72-second, intensely strong, narrowband radio transmission detected on August 15, 1977, by Ohio State University's Big Ear radio telescope. Source

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

The Ohio SETI Program — The Last Decades

by Keith CowingJune 10, 2026

The Ohio State University Radio Observatory (OSURO), known as the Big Ear, played a pivotal role in both radio astronomy and the Search for Extraterrestrial Intelligence (SETI).

Collection of disks with localized asymmetries in the dust continuum emission, shown at the same spatial scale based on the Gaia DR3 parallax. The colorscale is chosen arbitrarily to highlight the substructures. These images were presented in Ragusa et al. (2021) (IRAS 04158+2805), McLachlan et al. (2026) (AT Pyx), Pinilla et al. (2022) (LkHa 330), Francis & van der Marel (2020) (HD 34282), Vioque et al. (2026) (HD 97048, J16070854), Isella et al. (2018) (HD 163296), Hashimoto et al. (2021a) (ZZ Tau IRS), Norfolk et al. (2021) (RY Lup), Benisty et al. (2021) (PDS70), P´erez et al. (2018) (HD 143006), Dong et al. (2018) (MWC 758), Zagaria et al. (2025) (CQ Tau), Gonz´alez-Ruilova et al. (2020) (ISO-Oph 2), Long et al. (2018a) (CIDA 9), and Kurtovic et al. (2021) (MHO 6). -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Press Release, Stellar Cartography

An Archival Summary: 15 Years Of ALMA Observations On Disks And Planet Formation

by Keith CowingJune 9, 2026June 9, 2026

The Atacama Large (sub-)millimeter Array (ALMA) has been in scientific operations for almost 15 years.

Interstellar

A Look At Eight Outbursts Of Comet 7P/Pons-Winnecke

Reaction Mechanisms and Kinetics of CN and CCH with H2CS: Implications for Interstellar Sulfur Chemistry

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

Dust Colour, Phase Behaviour, And Monte Carlo Modelling Of Interstellar Comet 3I/ATLAS From 4 au Pre- to 4 au Post-Perihelion

Autonomous AI-Cosmoindustry and the Quiet Expansion Filter: A Threshold-Based Resolution of the Fermi Paradox

13CO And Potential Variability In β Pictoris b With GRAVITY+

The Carbon Isotope Ratio Of β Pic b With High-resolution Spectroscopy

First Detection Of HDO Ice In A Protoplanetary Disk

The Ohio SETI Program — The Last Decades

An Archival Summary: 15 Years Of ALMA Observations On Disks And Planet Formation

Perseverance Astrobiology Droid Has Completed A Martian Marathon

Machine Learning And Deep Learning For Exoplanet Detection And Atmospheric Characterization With JWST And The Upcoming Ariel Mission

Bioleaching Of Critical Trace Metals By Sphingomonas Desiccabilis: Substrate-driven Selectivity In Earth And Space Analogues

TESS Reveals The Puffiest Exoplanets Ever Found

An Agnostic Machine Learning Model of Photosynthetic Habitability