February 2025 – Page 3 – My WordPress Site

Left: color composite image of 114–426 using the F115W and F140M (both blue), F162M (green), F182M (yellow–green), and F277W (red) bands. Each of the four SW channel images (F115W, F140M, F162M, and F182M) were interpolated onto a 3 × 3 pixel subgrid (i.e., roughly 10 mas pixel−1) to allow precise alignment, and the LW channel image (F277W) was resampled to match. Right: an image of 114–426 in the F187N band, again interpolated onto a 3 × 3 pixel subgrid, showing the silhouette disk in maximum contrast against the Paα line. Each panel is 35 × 35 with north up and east left. The intensity of each image was scaled logarithmically to compress the dynamic range and enhance fainter details. -- The Astrophysical Journal

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

Water Ice in the Edge-on Orion Silhouette Disk 114–426 from JWST NIRCam Images

by Keith CowingFebruary 23, 2025February 23, 2025

Brine Shrimp Artemia franciscana -- Wikipedia

Analog Studies, Atmospheres, Climate, Weather, Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Mars, Space Life Science, Water/Hycean Worlds & Oceanography

The Brine Shrimp Artemia franciscana as a Model for Astrobiological Studies: Physiological Adaptations to Mars-like Atmospheric Pressure Conditions

by Keith CowingFebruary 23, 2025

Planetary occurrence statistic. Colours in the background refer to the detection limit map, from the non-reachable region (grey) to the unmissable one (white). The grey points represent the considered detections while the red points represent the candidates. The grey horizontal and vertical lines delineate the probed domains. The computed occurrence rates (along with their corresponding statistical bounds) are indicated at the center of each domain. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Stellar Cartography

Radial Velocity Homogeneous Analysis of M Dwarfs Observed With HARPS. II. Detection limits and Planetary Occurrence Statistics

by Keith CowingFebruary 23, 2025

Comparison of Venus and Earth atmospheric profiles (left) and depth-equivalent Earth altitude versus Venus altitude (right). Data of Venus atmosphere taken from [21]; Earth atmosphere represented with Linsley’s model [17, 22]. The vertical green dashed lines at the left panel indicate the extremes of the “Habitable Zone” (HZ) of reference [23] (venusian altitudes in the range 42.8 km to 62.2 km). -- astro-ph.EP

Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Habitable Zones, Microbiology & Virology, Origin & Evolution of Life, Terraforming & Geoengineering, Venus

The Venusian Chronicles

by Keith CowingFebruary 23, 2025February 23, 2025

Long- and short-cadence transit light curve data for HIP 41378 f, folded with orbital period Porb = 542.08 days. The reduced long-cadence data is shown in the left panels in scattered points; the short-cadence data is shown on the right with small points, then binned to 30 minutes and plotted with large points. The solid purple curve shows a randomly-drawn model from the posterior for comparison. The lower row presents the residual between the maximum likelihood model and the data. If we select the maximum likelihood model with f > 0.1, we obtain the residual shown in the dashed purple curve, which is disfavored with log-likelihood difference ∆ (log L) ≈ −3.4 -- astro-ph.EP

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

A Long Spin Period For A Sub-Neptune-mass Exoplanet

by Keith CowingFebruary 23, 2025February 23, 2025

Scientists have finally observed plastic ice (illustrated), a sort of hybrid phase between solid ice and liquid water that may form in the interiors of icy worlds like Neptune and Jupiter’s moon Europa. In plastic ice, the individual molecules are held in fixed positions within a crystal lattice, as if solid, while also being able to rotate, as if liquid. Institut Laue-Langevin Communications Office

Astrochemistry, Astrogeology, Cryobiology, Exoplanets, -moons, -comets, Exploration Gear & Tech, Icy Worlds

Plastic Ice VII – A Component of Ice World Interiors?

by Keith CowingFebruary 22, 2025February 22, 2025

Atmosphere retention distance for different atmospheric compositions, indicated by different colours, over time for a 1 M⊙ slowly rotating star. Above these lines, atmospheres can be retained. The green shaded area indicates the HZ. The dashed lines indicate Earth’s and Venus’s semi-major axis, denoted by their corresponding symbols. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones

Habitable Zone and Atmosphere Retention Distance (HaZARD) Stellar-evolution-dependent Loss Models of Secondary Atmospheres

by Keith CowingFebruary 22, 2025February 22, 2025

The crew of the Enterprise vies a map of the Sigma Draconis system and its three Class M planets - "Spock's Brain" - Paramount/CBS.

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Icy Worlds, Lava / magma ocean / Volcanic Worlds, Nomenclature, Systematics, Natural History, Science Fiction, Stellar Cartography, Water/Hycean Worlds & Oceanography

Architecture Classification For Extrasolar Planetary Systems

by Keith CowingFebruary 22, 2025February 22, 2025

Astronomy & Telescopes, Beta Pictoris, Exoplanets, -moons, -comets, Imaging & Spectroscopy

Dynamics of the Beta Pictoris Planetary System and Possibility of an Additional Planet

by Keith CowingFebruary 22, 2025February 22, 2025

Enceladus Cassini phase curves from Li et al. (2023), with their corresponding colour filter used in this analysis. The datapoint colours are a crude guide for the different wavelengths of the filters. Some of the filters do not have alternative names. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Enceladus, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Jupiter

Enceladus And Jupiter As Exoplanets: The Opposition Surge Effect

by Keith CowingFebruary 21, 2025February 21, 2025