December 2025 – Page 3 – My WordPress Site

The Kepler exoplanet candidate population around FGK stars used in the analysis of S. Bryson et al. (2021), shown in period and radius, both colored and sized by catalog reliability with exoplanet radius error bars. The background color map and contours indicate detection completeness. The rectangles show example η⊕ definitions from different authors. Adapted from S. Bryson et al. (2020a). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Stellar Cartography, Water/Hycean Worlds & Oceanography

Why Estimating η⊕ Is Difficult: A Kepler-Centric Perspective

by Keith CowingDecember 29, 2025December 29, 2025

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

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

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

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

Comparison of Arctic Ocean FSLE snapshots from the two simulations during March. Brighter regions (high FSLE) indicate more vigorous horizontal stirring. Left panel: present-day conditions; right panel: future conditions representing a quadrupling of atmospheric CO2. Basemap credit: NASA Blue Marble. Figure credit: YI Gyuseok. Credit Institute for Basic Science

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Water/Hycean Worlds & Oceanography

Water Planet: More Polar Ocean Turbulence Due To Planetary Warming

by Keith CowingDecember 29, 2025December 29, 2025

(B) Diagnosis of cloud structure (color), geopotential anomalies (solid lines representing positive values and dotted lines representing negative values), and horizontal velocity fields (red arrows). (C) Top-of-atmosphere thermal flux corresponding to the cloud structure shown in (B). -- Science Advances via PubMed

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Desert Worlds, Exoplanets, -moons, -comets

Large-amplitude Variability Driven By Giant Dust Storms On A Planetary-mass Companion

by Keith CowingDecember 29, 2025December 29, 2025

Graphical Abstract -- ACS via Pubmed

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

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

by Keith CowingDecember 29, 2025December 29, 2025

ID: ESP_044892_1695 date: 23 February 2016 altitude: 261 km larger image NASA/JPL-Caltech/University of Arizona

Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Desert Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Mars, Missions & Hardware

Mars Orbital Recon: Possible Sulfate Deposits In West Melas Chasma

by Keith CowingDecember 28, 2025December 28, 2025

Distribution of the targets observed in this work across the Milky Way in white “+” symbols along with their identifiers, as listed in Table 1. The red asterisk and Sun symbols mark the Galactic centre at (0, 0) kpc and the position of the Solar System at (0, −8.15) kpc, respectively (Reid et al. 2019). The sources are projected onto the Galactic plane with parallax-based distances from Reid et al. (2019). The underlying Milky Way spiral arm pattern follows the log-periodic model from the same study, with colours adapted from Jacob et al. (2022). The background image, is an artist’s impression of the large-scale structure of the Milky Way, courtesy of ESA/Gaia/DPAC/Stefan Payne-Wardenaar. -- astro-ph.GA

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

APEX Survey Of Interstellar HCl: 35Cl/37Cl Isotopic Ratios In Dense Cores And Outflows

by Keith CowingDecember 28, 2025December 28, 2025

Planetary formation - Grok via Astrobiology.com

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Intelligence & Language

New SwRI Laboratory To Study The Origins Of Planetary Systems

by Keith CowingDecember 28, 2025

Stability analysis of the TOI-6041 system. The phase space of the system is explored by varying the orbital period Pi and eccentricity ei of each planet independently. For each initial condition (Table 4), the system is integrated over 10 kyr, and a stability criterion is derived with the frequency analysis of the mean longitude. The chaotic diffusion is measured by the variation in the frequencies. The color scale corresponds to the logarithmic variation in the stability index used in (Correia et al. 2010). The red zone corresponds to highly unstable orbits, while the dark blue region can be assumed to be stable on a billion-year timescale. White dashed lines indicate the nominal orbital periods reported in Table 4. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy

Giant Outer Transiting Exoplanet Mass (GOTEM) Survey.VII. TOI-6041: A Multi-planet System Including A Warm Neptune Exhibiting Strong TTVs

by Keith CowingDecember 28, 2025December 28, 2025