Pluto Archives

The northern and eastern portions of Sputnik Planitia (SP)

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 […]

NIRSpec average spectrum of Titan (black) compared with a radiative transfer calculation in which the surface albedo decreases smoothly with wavelength beyond 4.9 µm (red). The blue line shows the difference between the observed and synthetic spectra, shifted by 0.005 for clarity. The 5.11-µm absorption is clearly missing in the model. The small mismatch below 4.93 µm is due to a component of the non-LTE CO emission not included in the model. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Pluto, Status Report, Titan

An Unidentified Absorption Feature At 5.11 μm On The Surface Of Titan And Pluto From JWST Spectroscopy

by Keith CowingJune 12, 2026June 12, 2026

Titan possesses a thick N2-CH4 atmosphere that makes it difficult to study its surface spectroscopically. The chemical composition of the solid surface of Titan thus remains very uncertain.

Three station light curves of 2002 XV93’s stellar occultation on 10 January 2024. The flux points (points with error bars) observed at Kyoto (a), Kiso (b) and Fukushima stations (c) overlaid with the synthetic light curves (red lines, assuming a pure CH4 atmosphere and a best-fit surface pressure of 124 nanobars) are shown as a function of time. In panel c, the gray points are the flux points for the individual exposures, and the black points are those binned by a factor of 8. The vertical arrow represents the closest approach time to the shadow edge at Fukushima, at 13:12:50.818 UT. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Pluto, Status Report

The First Detection Of An Atmosphere On A Trans-Neptunian Object Beyond Pluto

by Keith CowingMay 8, 2026May 8, 2026

Trans-Neptunian objects (TNOs) in the outer Solar System are predominantly small, icy worlds long presumed to be atmosphereless except for the largest bodies.

Details of the interior models of Uranus and Neptune. Top: Illustration of the three-layer internal structure model assumed. Both the envelope and mantle contain hydrogen, helium, ices, and rocks, with the mantle expected to have a higher concentration of ices and rocks. The core is composed entirely of rocks. Bottom: Envelope metallicity versus mantle metallicity for interior models of Uranus and Neptune. Each dot represents a model that fits both the gravitational data and radius of the respective planet. The color scale indicates the core mass. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Neptune, Status Report, Uranus

Reassessing Planetary Composition: Evidence Of Rock-dominated Envelopes In Uranus And Neptune

by Keith CowingApril 17, 2026April 17, 2026

Although Uranus and Neptune are commonly classified as ice giants, their exact compositions remain poorly constrained. Recent studies of outer Solar System bodies challenge the traditional view that these planets […]

Major icy bodies in the Solar System, with the Earth’s moon to scale. The images are shown at the proper relative size. From NASA’s Planetary Photojournal (https://photojournal.jpl.nasa.gov/), Earth’s Moon (PIA00302), Europa (PIA00502), Ganymede (PIA00716), Callisto (PIA03456), Mimas (PIA06258), Enceladus (PIA06254), Tethys (PIA07738), Dione (PIA08256), Rhea (PIA08256), Titan (PIA08256), Hyperion (PIA07740), Iapetus (PIA08384), Phoebe (PIA06064), Miranda (PIA18185), Ariel (PIA01534), Umbriel (PIA00040), Titania (PIA01979), Oberon (PIA00034), Triton (PIA00317), Pluto (PIA19952). -- astro-ph.EP

Ariel, Astrogeology, Callisto, Ceres, Charon, Dione, Enceladus, Europa, Ganymede, Iapetus, Ice Giant, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mimas, Miranda, Missions & Hardware, Moon, Oberon, Phoebe, Pluto, Polar / Alpine Expeditions, Rhea, Status Report, Tethys, Titan, Titania, Triton, Umbriel, Water/Hycean Worlds & Oceanography

Icy Worlds: Moons And Dwarf Planets

by Keith CowingDecember 1, 2025December 1, 2025

In the outer solar system beyond Jupiter, water ice is a dominant component of planetary bodies, and most solid objects in this region are classified as icy bodies.

Transmission spectra obtained on the Titan 1 and Exoplanet 2 PAMPRE haze analogs (see Table 1) from 0.3 to 2.5 µm. (top) Data and analysis using the Swanepoel method for the Titan 1 sample produced from a gas mixture of 90% N2 and 10% CH4. (bottom) Data and best fit using Cauchy and Tauc-Lorentz dispersion laws for the Exoplanet 2 analog produced from 95% Ar and 5% CH4 in the initial gas mixture. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Pluto, Status Report, Titan

Refractive Indices Of Photochemical Haze Analogs For Solar System And Exoplanet Applications: A Cross-laboratory Comparative Study Between The PAMPRE And COSmIC Experimental Set-ups

by Keith CowingNovember 22, 2025November 22, 2025

Previous observations of Titan, Pluto and Solar System gas giants along with recent observations of exoplanet atmospheres with the James Webb Space Telescope taught us that photochemical hazes are ubiquitous […]

Stellar Cartography tracking session - Paramount/Astrobiology.com

Away Teams & Field Reports, Budgets and Policy, Imaging & Spectroscopy, Interstellar, Mapping, Geodesy, Cartography, Bathymetry, Missions & Hardware, Policy, Status Report, Stellar Cartography

Stellar Cartography: A Demonstration Of Interstellar Navigation Using New Horizons

by Keith CowingJuly 1, 2025July 1, 2025

Editor’s note: Those of you in the space community know that NASA Science is facing an immense budget cut. Dozens of missions have been cancelled and many missions that are […]

Images of the trans-Neptunian objects (TNOs) Pluto [left] and Arrokoth [right], the primary flyby targets of NASA’s New Horizons spacecraft in 2015 and 2019. NASA’s James Webb Space Telescope is capable of obtaining observations for in-depth studies of a wide range of TNOs that both complement, and go beyond what was learned by New Horizons. (Image credits: NASA/SwRI/JHU-APL)

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Cryobiology, Icy Worlds, Imaging & Spectroscopy, Pluto, Status Report

Webb Reveals The Ancient Surfaces of Trans-Neptunian Objects

by Keith CowingFebruary 13, 2025February 13, 2025

Trans-Neptunian objects (TNOs) are icy bodies ranging in size from Pluto and Eris (dwarf planets with diameters of about 1,500 miles) down to tens of miles (Arrokoth) and even smaller. […]

Snapshot of Pluto and Charon during kiss-and-capture. Credit Robert Melikyan and Adeene Denton.

Astrogeology, Habitable Zones, Icy Worlds, Pluto, Press Release

An Origin For Pluto’s Subsurface Ocean?

by Keith CowingJanuary 7, 2025January 7, 2025

Billions of years ago, in the frigid outer reaches of our solar system, two icy worlds collided. Rather than destroying each other in a cosmic catastrophe, they spun together like […]

Triton, Neptune’s main satellite, passed in front of a star on October 6, 2022. This phenomenon prompted a vast campaign of observations in India, China and from space, led by a scientist from Observatoire de Paris - PSL, to measure the atmospheric pressure prevailing on its surface. Published in the journal Astronomy & Astrophysics on February 27, 2024, the value obtained raises a number of questions.

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Press Release, Triton

Triton Atmospheric Pressure: A New Value Is Obtained

by Keith CowingDecember 19, 2024September 18, 2025

The observation of a stellar occultation by a Solar System object is a very powerful method for measuring its dimensions, as well as possibly detecting rings, revealing an atmosphere and […]