icy world Archives

[TOP] Example observations of (2060) Chiron for survey/telescopes (left) ATLAS, (middle) ZTF, and (right) LCO/LOOK. [BOTTOM] Example observations of 103P/Hartley 2 for survey/telescopes (left) ATLAS, (middle) ZTF, and (right) LCO/LOOK. -- astro-ph.EP

Comets and Asteroids

Multi-year Ground-Based Survey Photometry of Active Comet 103P/Hartley 2 and Centaur (2060) Chiron: A Tale of Two Comets in the Pre-LSST Era

by Keith CowingJuly 5, 2026July 5, 2026

[astro-ph.EP] Comets and Centaurs trace the evolution of trans-Neptunian objects (TNOs) into the inner solar system.

The northern and eastern portions of Sputnik Planitia (SP)

Pluto

Evidence For Possible N2 Basal Flow Beneath Pluto Northern Sputnik Planitia

by Keith CowingJune 30, 2026June 30, 2026

[astro-ph.EP] Sputnik Planitia (SP) on Pluto is a large, predominantly N2 ice-filled basin with a surface area of one million square kilometers; it is among the most spectacular surface features […]

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

Uncategorized

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 […]

Coordinate systems. (a) Schematic of the coordinate systems. e𝜃 and er are the meridional (latitudinal) direction and the vertical direction (opposite to the gravitational direction), respectively. ez and es are the axial direction aligned with planetary rotation and the radial direction perpendicular to it, respectively. e𝜙 represents both the zonal direction in spherical coordinates and the azimuthal direction in cylindrical coordinates. (b) Distribution of 𝐻𝑧 in the simulation with Enceladus-like parameters: a core radius of 192 km and an ocean surface radius of 232 km. Outside the tangent cylinder, 𝐻𝑧 is kept constant. In (a) and (b), gray dashed lines indicate the tangent cylinder. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Icy Worlds, Water/Hycean Worlds & Oceanography

Parameterizing Slantwise Convection In Icy Moon Oceans

by Keith CowingJune 25, 2026June 25, 2026

Convection in icy moon oceans is strongly influenced by rotation, organizing into slantwise columnar structures aligned with the planetary rotation axis. They generate significant meridional heat transport, which can affect […]

Illustration of key factors affecting subsurface ocean habitability and possible chemical evolution in icy moons Factors with question marks are still under debate. -- The Innovation via PubMed

Icy Worlds

Dynamic Controls On Subsurface Water Chemistry And Habitability On Icy Moons

by Keith CowingJune 23, 2026June 23, 2026

Icy moons are natural satellites whose surfaces contain a substantial fraction of frozen materials, most notably water ice.

An artist's rendering of Europa and Jupiter based on images sent by visiting spacecraft. Europa is the closest orbiting of the three Jupiter’s large ‘Galilean’ moons to be visited by Juice – any human astronaut that lands there would receive a lethal radiation dose on a timescale of hours. And spacecraft electronics are almost as susceptible to radiation as human biology. CREDIT NASA/JPL-Caltech

Europa, Meteorites & Asteroids, Origin & Evolution of Life, Panspermia, Planetary Protection & Biosafety, Status Report, Water/Hycean Worlds & Oceanography

Earth As A Potential Source Of Llife For Europa’s Subsurface Ocean

by Keith CowingJune 22, 2026June 21, 2026

The paper discusses the possibility of dust particles containing living bacteria ejected from Earth reaching Europa and landing on its surface.

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 […]

This artist's impression shows radar waves from the NASA Goldstone Solar System Radar pinging one of Jupiter’s moons, Europa. The radar waves penetrate Europa’s icy surface before bouncing back to be collected by the NSF Green Bank Telescope on Earth. Credit: NSF/AUI/NSF NRAO/P.Vosteen

Callisto, Europa, Ganymede, Habitable Zones, Icy Worlds, Journal articles, Press Release, Water/Hycean Worlds & Oceanography

Radar Echoes From Europa Reveal Secrets Beneath the Ice

by Keith CowingJune 18, 2026June 18, 2026

A team of scientists has used NASA’s Goldstone Solar System Radar and the U.S. National Science Foundation Green Bank Telescope (NSF GBT) to carry out the most extensive radar study […]

ID: ESP_087131_2640 date: 26 February 2025 altitude: 316 km larger image

Astrogeology, Biogeochemical Cycles & Geobiology, Desert Worlds, Icy Worlds, Imaging & Spectroscopy, Mars, Status Report

The Spring Awakening of Martian Polar Dunes

by Keith CowingJune 16, 2026June 16, 2026

During the Martian winter, carbon dioxide ice (dry ice) blankets various landforms, including dunes, in the northern high latitudes. As spring arrives, the ice sublimates, causing unique changes on the […]