DPS 58: Days 3 and 4

Editor’s Note: This week, we’ve been posting summaries of selected sessions from the 58th Division for Planetary Sciences (DPS) meeting in Spokane, WA. The usual posting schedule for AAS Nova will resume on 2 November.

Table of Contents:

• Press Conference: Studies of Titan, Rocky Body Surfaces, 10 Years of Juno, and Rubin Studies of TNOs
• Press Conference: Studies of Rocky Body Atmospheres, the OSIRIS-Rex Mission, Connections to Exoplanets, and Characterization of the Outer Solar System
• 2026 DPS Masursky Award: Saving NASA Science (Casey Dreier and Jack Kiraly)
• 2026 DPS Urey Prize Presentation: Characterizing Exoplanet Climates from Close-In Gas Giants to Temperate Rocky Planets (Tad Komacek)
• 2026 DPS Urey Prize Presentation: Unlocking Planetary Histories Through Subsurface Stratigraphies (Ali Bramson)
• 2026 DPS Alexander Prize: Titan: Ingredients for Life (Catherine Neish)
• 2026 DPS Kuiper Prize: New Worlds — Legacy Processes (Mark Marley)

---

Press Conference: Studies of Titan, Rocky Body Surfaces, 10 Years of Juno, and Rubin Studies of TNOs (Briefing video)

Devin Hoover (University of Arizona) described a study of Lyman-α (121.6 nm) emission from Titan. Titan, Saturn’s largest moon, is the only moon in the solar system with a significant atmosphere. Within Titan’s atmosphere, photochemistry creates a thick layer of haze and splits apart methane molecules, liberating hydrogen atoms that can escape to space. By monitoring the Lyman-α emission from this escaping hydrogen, researchers can study depletion of the methane in Titan’s atmosphere.

Titan’s Lyman-α emission was recorded by the Cassini mission, but many of those observations haven’t been analyzed. Hoover used a new radiative transfer model to interpret the Lyman-α emission, considering contributions from light scattered by hydrogen atoms as well as a direct contribution from interplanetary hydrogen. The team found hydrogen escape rates of order 10²⁴–10²⁵ hydrogen atoms per second, which is roughly consistent with theory and previous calculations. They also calculated methane escape rates, finding that the methane escape rate is highly sporadic and can be as rapid as 10⁷–10⁹ molecules cm^-2 s^-1. This is significantly faster than predicted by theory, and Hoover’s team has proposed that when lighter species like hydrogen escape from Titan’s atmosphere, they drag methane along with it, boosting its escape rate. If this explanation is correct, it would have important implications for the study of planetary atmospheres in general.

C. Adeene Denton (Southwest Research Institute) discussed new work on the creation of our Moon. In the canonical scenario, a Mars-sized protoplanet called Theia crashed into the proto-Earth, forming a debris disk around the proto-Earth, and the Moon coalesced out of the debris disk. Modeling of this scenario typically uses smoothed-particle hydrodynamics simulations, which approximate the colliding bodies as fluids. This means that the bodies will deform like fluids do as they interact, and in the Moon-formation scenario, this leads Theia to be fully destroyed in the impact, creating a melt-dominated debris disk. The Moon is then built back up out of this debris disk in days to years.

Now, computational capabilities have increased, and modeled materials can have material strength — the ability of a material to resist deformation. Denton’s team found that incorporating material strength changes the outcome of the modeling: Theia splits into two pieces, one of which remains intact and becomes the Moon, resulting in nearly immediate Moon formation without a debris disk. The modeled newborn Moon is comparable in mass and rock/iron ratio to the present-day Moon. This scenario has interesting implications for age-dating the formation of the Moon, since the material strength of the protoplanets involved depends on their temperature and thus their age. Earlier in solar system history, when the protoplanets were hotter, it’s possible to obtain intact satellites, while later in history, when things are cooler, the surviving satellites are smaller. Future modeling may help to identify detectable differences between these scenarios.

Gokce Inal (Ohio State University) examined the impact of another recent technological advance: AI. Inal’s research was motivated by two questions: 1) Can AI understand the lunar surface the way a planetary scientist does? 2) Can AI make recommendations like a mission planner would? Inal’s team developed LLaVA-Le, an AI agent that can answer questions about orbital images of the Moon’s surface the way a scientist would. Then, a second AI agent called LUMINA can act as a mission planner, developing a ranked list of landing sites based on public NASA maps and landing rules. LUMINA created a list of 30 potential landing sites within a 72,000 km² region at the Moon’s south pole, and all seven of NASA’s candidate lunar landing regions are in the AI’s top 16 regions.

LUMINA developed its recommendations based on a broad-to-narrow process that started with slope maps before screening based on temperature, sunlight, elevation, minerals, and other factors. The advantages of this technique for mission planning are that 1) each site is accompanied by the evidence underlying its selection, 2) it’s fast and easy to redo the site selection when a requirement or map changes, and 3) every spot on the map is checked, resulting in an analysis of 6,000 regions within 5 degrees of the south pole.

NASA’s Juno mission has now been orbiting Jupiter for a little more than 10 years. Juno Principal Investigator Scott Bolton (Southwest Research Institute) described some of its key findings and how the mission has evolved over time. Juno is the first solar-powered mission to travel to Jupiter, and it monitors our solar system’s largest planet with a suite of 11 instruments and 30 sensors. Over time, Juno’s orbit has shifted, and the mission has been able to gain new perspectives on Jupiter’s atmosphere and pass close to several of its moons.

Early discoveries from the Juno mission include the finding that the atmosphere is not well mixed, and that the planet’s core, rather than being small and metal rich, is large, diluted, and depleted of heavy elements. Together, these findings suggest that sending a probe into the atmospheres of each of our solar system’s giant planets is unlikely to illuminate solar system history as once hoped. (So far, only Jupiter has been probed in this manner.) Juno also revealed Jupiter’s polar cyclones in vivid detail, showing that they have warm cores just like Earth’s tropical cyclones. Juno’s observations were also critical for constraining the thickness of the ice shells on several moons and demonstrating that while Io does not harbor a massive subsurface magma ocean, it likely has small, separate seas of magma. Now, as the mission continues, Juno will explore new regions and undertake new science.

The NSF–DOE Vera C. Rubin Observatory is just getting started, and already the discoveries are starting to roll in. Megan Schwamb (Queen’s University Belfast) announced the discovery of several Neptune trojans with Rubin. The Neptune trojans are small, icy bodies that occupy Neptune’s orbit, leading and trailing the planet by 60 degrees. Trojans are important probes for the history of the solar system, and they play a crucial role in testing models of solar system evolution involving migration of the giant planets.

Neptune and Jupiter host the majority of the trojans in our solar system. So far, we’ve discovered about 16,000 Jupiter trojans and just 32 Neptune trojans — but researchers suspect that there are actually 4–10 times more Neptune trojans than Jupiter trojans. Nearly all of the known Neptune trojans inhabit the swarm that leads Neptune in its orbit, while just two occupy the trailing swarm. It’s not yet known whether these clouds of objects are actually symmetrical because the trailing cloud has been projected against the crowded plane of the Milky Way for 15 years. Now, Rubin has already discovered three trailing Neptune trojans (two confirmed and one candidate). By monitoring these objects and determining their colors, Rubin has also shown that the leading and trailing clouds of Neptune trojans have similar compositions. This is just the beginning: Rubin’s Legacy Survey of Space and Time will discover tens to hundreds of new Neptune trojans.

Return to Table of Contents.

---

Press Conference: Studies of Rocky Body Atmospheres, the OSIRIS-REx Mission, Connections to Exoplanets, and Characterization of the Outer Solar System (Briefing video)

Edward (Beau) Bierhaus (Lockheed Martin) reported on a serendipitous experiment enabled by the OSIRIS-REx mission to the asteroid Bennu. OSIRIS-REx touched down on Bennu, a 500-meter-wide rubble pile near-Earth asteroid, and collected a sample to return to Earth. This process required the lander to fire its thrusters and lift off from the surface of the asteroid, unintentionally carrying out an experiment relevant for planetary defense.

Some near-Earth asteroids are potentially hazardous, and it’s not yet known how these objects respond to outside forces, which limits our ability to respond in a planetary defense scenario. (The Double Asteroid Redirection Test mission purposefully slammed a small spacecraft into an asteroid to test one approach to changing the course of an oncoming asteroid.) Bierhaus and collaborators modeled the effects of the thrusters on the surface of Bennu, showing that the footprints of the thruster plumes correlate with the erosion seen on the surface. OSIRIS-REx’s thrusters displaced more than 17 cubic meters of material, moving an estimated 16,000 kg of rubble. This also revealed that Bennu’s surface had a more complex structure than expected. Overall, this experiment showed that thrusters can move a lot of material on small bodies, offering a new way to probe the surface of these bodies without touching down — an experiment that OSIRIS-APEX will soon carry out on the asteroid Apophis.

Steven Desch (Arizona State University) described a search for the answer to a question posed 17 years ago: why is the Sun more depleted in refractory materials than 82% of solar twins? Early on, it was thought that this mystery could be solved by the presence of our solar system’s giant planets: perhaps our star is depleted in refractory materials (materials that remain solid up to relatively high temperatures) because these materials are locked away inside the giant planets. Further research disproved this theory, and now, Desch’s team has a new hypothesis: astronomers’ favorite scapegoat — magnetic fields — are to blame.

If the ratio of mass and magnetic flux in a molecular cloud is below a certain value, the magnetic field can slow the cloud’s collapse. This slowdown is especially effective on small, electrically charged dust grains, while larger dust grains are unaffected. This means that if magnetic fields are present, stars accrete less dust — a reservoir for refractory materials — and likely form with lower metallicity than their parent molecular clouds. Taking the effects of magnetic fields into account, Desch’s team found a range of refractory material depletions that aligned well with what is seen for solar twins, as well as a value for the Sun that matches observations. If the Sun is less metal rich than the cloud it came from, that would mean that the Sun could have been born much closer to the galactic center. If stars don’t match the metallicity of their parent molecular clouds, that would have huge implications, and this finding has not yet been incorporated into models of star formation.

Jordan Steckloff (Planetary Science Institute) discussed a conundrum regarding the formation of debris disks around white dwarfs. When a star like the Sun reaches the end of its main-sequence lifetime, it evolves into a red giant and eventually leaves behind its exposed stellar core in the form of a white dwarf. A white dwarf should radiate as a blackbody, but observations show that many white dwarfs have more infrared emission than expected. These infrared excesses are often interpreted as evidence for close-in disks of debris. Because a star’s transition to a red giant and then a white dwarf should destroy any close-in objects, these disks must form from material that has migrated inward during the star’s red giant phase.

Steckloff considered how the strength of these materials affects the size of the debris that forms during migration, finding that the characteristic size is in the range of 100–1,000 meters — much larger than the pulverized dust thought to inhabit a white dwarf’s debris disk. While the mystery of how a white dwarf’s dusty disk comes to be remains unsolved for now, future work that explores the impact of collisions or rotational disruption may hold clues.

Elizabeth Silber (Sandia National Laboratories) brought the discussion back to the OSIRIS-REx mission, describing what was learned from the journey of its sample return capsule through Earth’s atmosphere. Silber’s team is interested in what happens when objects slam into Earth’s atmosphere. These impacts generate shockwaves and low-frequency sound called infrasound. By monitoring the infrasound from an atmospheric impact, scientists hope to use models to extract the properties of the impacting object. However, it can be extremely difficult to determine how large the impacting object was and how much energy it deposited in our atmosphere, and it’s hard to know anything about the object itself without discovering an associated meteorite.

By studying an object with known properties — the sample return capsule — the team was able to test their models of shockwave physics. Since the trajectory of the capsule was known in advance, they deployed 39 infrasound detectors along its path and compared the measured signal against the predictions of multiple shockwave models. They will apply what they learned from this study to situations where they don’t know the properties of the impacting object, helping to characterize incoming objects and predict their effects on Earth’s atmosphere.

Return to Table of Contents.

---

2026 DPS Masursky Award: Saving NASA Science, Casey Dreier and Jack Kiraly (The Planetary Society)

The 2026 Harold Masursky Award for Meritorious Service to Planetary Science was awarded to Casey Dreier and Jack Kiraly of the Planetary Society for “exceptional service to planetary science and space exploration.” Dreier described the Save NASA Science advocacy campaign, which worked to prevent a devastating 47% cut to NASA funding proposed in the fiscal year 2026 President’s Budget Request. This campaign unfolded on multiple levels, from highly successful social media posts (reaching 9 million views on Instagram reels about planetary science policy) to the re-establishment of the Congressional Planetary Science Caucus. Part of the campaign was the largest Day of Action for space science in history, bringing more than 300 advocates to Washington, DC. Dreier highlighted the year-round advocacy efforts of the Planetary Society, including the creation of a dashboard to track the scientific impact of NASA missions. These collective actions were successful, and Congress overwhelmingly rejected the proposed cuts.

Kiraly expanded on the year-round advocacy efforts of the Planetary Society and described upcoming opportunities. In January, there will be 90 or more new members of Congress, which may be a record. This presents an incredible opportunity to define the issue of planetary science funding for more than a fifth of the new Congress. The Planetary Society aims to reach these new members with the next Save NASA Science Day of Action, which will take place 31 January and 1 February 2027 in DC. Kiraly hopes that they can break last year’s record for participation and ward off another existential threat to space science. Check out the Save NASA Science Action Hub to learn more and get involved!

Return to Table of Contents.

---

2026 DPS Urey Prize Presentation: Characterizing Exoplanet Climates from Close-In Gas Giants to Temperate Rocky Planets, Tad Komacek (Oxford University)

Tad Komacek was awarded a 2026 Harold C. Urey Prize in Planetary Science for “pioneering research in planetary science, which has fundamentally advanced our understanding of planetary atmospheres within the solar system and beyond.” In this presentation, Komacek discussed his work on characterizing exoplanet atmospheres, specifically of hot Jupiters and temperate rocky planets around M dwarfs.

Hot Jupiters are completely unlike anything we have in our solar system. These planets are close to their stars, tidally locked, strongly irradiated, and extremely hot, with equilibrium temperatures greater than 1000K. The irradiation gradient on these planets creates strong pressure gradients that drive intense winds. These rapid winds should bring things into equilibrium quickly, but observations show that hot Jupiters have day–night temperature differences of hundreds of degrees. Komacek showed that damping of gravity waves is responsible for maintaining this temperature difference.

Hotter hot Jupiters have a larger temperature contrast, but this trend reverses at extremely high temperatures, in the rarefied realm of ultra-hot Jupiters, which have equilibrium temperatures >2200K. Above this temperature, molecular hydrogen dissociates, and the energy absorbed by dissociation (and released by recombination elsewhere in the atmosphere) changes these planets’ atmospheric dynamics, leading to a counterintuitive reduction of the day–night temperature gradient.

Komacek has also used models to explore mineral clouds on hot Jupiters. Using WASP-43b as an example, he showed that certain planets’ phase curves can’t be matched by cloudless models. Further work on observations of WASP-43b from JWST has suggested that this planet only has clouds on its nightside, prompting a need for models that couple clouds, circulation, and radiation.

Turning to temperate planets around M dwarfs, Komacek showed that though these planets might be rocky like Earth, there’s no reason for them to be truly Earth-like. Because these planets are slowly rotating, they have large day–night temperature gradients — like hot Jupiters — rather than equator–pole temperature gradients like Earth. Many of these planets have lots of clouds on their daysides, softening spectral features and making their atmospheres difficult to study, with the faintest spectral features on planets with rotation periods longer than 10 days.

Komacek also described modeling work from a member of his research group who has estimated the thermal emission from M-dwarf exoplanets that are not transiting. This showed that the thermal emission, including certain spectral features, could be detectable for some planets by upcoming missions like the Habitable Worlds Observatory.

Return to Table of Contents.

---

2026 DPS Urey Prize Presentation: Unlocking Planetary Histories Through Subsurface Stratigraphies, Ali Bramson (Purdue University)

Ali Bramson was awarded a 2026 Harold C. Urey Prize in Planetary Science for “her groundbreaking contributions to planetary science.” In a delightful extension of her childhood fascination with columnar basalts and the planetary history they convey, Bramson now explores planetary history through stratigraphy: the study of rock and other layers

On Mars, Bramson has examined the ice layers making up the polar caps, where aerial images show layers in the exposed ice. Radar observations offer a different perspective, allowing researchers to probe even deeper. Radar data has shown that Mars’s north and south polar ice caps are fundamentally different from one another, though each ice cap shares similarities with the small, ice-filled craters that dot the surface around them. At the north pole, the ice cap and surrounding craters are similar deep down, but show some differences in the top 5 meters, suggesting that their lower layers of ice were placed concurrently or under similar environmental conditions, while modern-day ice is being shaped by the local environment. At the south pole, some craters look similar to the ice cap, while others do not. This suggests that these ice deposits formed under two different sets of environmental conditions.

Moving away from the poles, visible ice becomes scarce, but you need only scratch the surface to find it. This was demonstrated by the Phoenix lander in 2008, when its robotic arm unearthed (unmarsed?) a swath of ice just a few centimeters below the surface. This discovery occurred around 68 degrees north, and ice — if present — is likely concealed under a much thicker layer of material at lower latitudes. Luckily, radar can reveal this ice as well. Bramson’s team examined a curious set of craters in Arcadia Planitia with a terraced appearance: evidence for subsurface layers. Using these craters, they determined that a subsurface ice sheet tens of meters thick and covering 1.2 million square kilometers resides under Arcadia Planitia. Recent impacts that expose this ice supports this assessment.

To close out the Mars portion of the talk, Bramson emphasized that studying ice on Mars is critical for constraining the planet’s climate; understanding its habitability, especially in terms of its water budget; and enabling future human explanation. She concluded with a brief detour to the Moon, where her team works to understand the extent of a different buried material: ancient lava flows that created the dark areas on the Moon’s surface. Using radar, Bramson’s team has shown that the buried lava flows are three times more extensive than thought, which important for our understanding of the Moon’s past volcanism.

Return to Table of Contents.

---

2026 DPS Alexander Prize: Titan: Ingredients for Life, Catherine Neish (University of Western Ontario and the Planetary Science Institute)

Catherine Neish was awarded the 2026 Claudia J. Alexander Prize in Planetary Sciences for “her scientific, leadership, and collaborative contributions to planetary science.” Neish’s topic was Titan, the only moon in our solar system with a dense atmosphere, and an intriguingly Earth-like one at that. Titan’s thick atmosphere is rich in nitrogen, and reactions between nitrogen, methane, and incoming photons create a smoggy blend of organic compounds.

Our understanding of Titan’s atmosphere and surface has evolved dramatically since 1944, when Gerard Kuiper discovered the moon’s atmosphere and saw that it contained methane. When Voyager 1 paid a visit in 1980, it found that the atmosphere was rich in nitrogen, expanding our understanding of Titan’s atmospheric chemistry, but the spacecraft carried no instruments capable of peering through the atmosphere to the surface. Finally, starting in 2004, the Cassini–Huygens mission revealed Titan as a strangely Earth-like world, with sand dunes, bright plains, lakes, and a young, weathered surface relatively unmarked by impact craters.

Thanks to Voyager and Cassini, Neish said, we now know that Titan has all the ingredients needed for life: an energy source (mainly the Sun), the necessary elements (carbon, hydrogen, nitrogen, and oxygen), and a solvent. Titan actually has two plausible solvents: liquid methane and water. Liquid methane likely makes a poor solvent for the chemical reactions necessary for life, and any life that relies on methane would be so different from life as we know it that we might not even know what to look for. Water, on the other hand, we know to be a great solvent — but on Titan it’s frozen hard as rock.

Titan’s water can liquefy briefly after an impact, potentially allowing the chemical reactions necessary for life to happen in the pool of impact melt. As a graduate student, Neish studied this possibility by exposing lab-grown Titan haze particles to liquid water. Reporting on her results as part of a program on the Discovery Channel in 2008, she showed that multiple amino acids found in life on Earth formed in this mixture in hours to days — likely fast enough to form on Titan before the impact melt refreezes. (In this program, she also cheerfully informed the audience that it would take a surprisingly long time to freeze to death in Titan’s 95K chill, so suffocation is probably how you’d go!)

Energized by this finding, Neish was excited for a mission to Titan that could search for evidence of amino acid formation. But when the results of the decadal survey rolled out in 2011, a Titan mission didn’t make the list. After pivoting to work on impact melt of the Moon, Neish got a call from a colleague inviting her to work on a proposal for a new Titan mission. That mission — Dragonfly — is now scheduled for launch in 2028, with arrival at Titan in the mid-2030s. Dragonfly will touch down between dunes near Selk crater, a young impact crater near Titan’s equator, offering an opportunity to study a region where organic materials and liquid water might have mixed in the past.

Return to Table of Contents.

---

2026 DPS Kuiper Prize: New Worlds — Legacy Processes, Mark Marley (University of Arizona)

Mark Marley was awarded the 2026 Gerard P. Kuiper Prize in Planetary Sciences for “outstanding contributions to the field of planetary science.” Marley centered this talk on processes that have been discovered and understood within the solar system, then extended to exoplanets and brown dwarfs, helping to place the planets in our solar system within the broader context of substellar worlds.

Marley focused on three processes: disequilibrium chemistry, clouds, and temperature inversions. Taking Jupiter as an example, Marley recounted the discovery of carbon monoxide in Jupiter’s atmosphere — a molecule that, under equilibrium chemistry, shouldn’t have been there. Researchers discovered that carbon monoxide was present because the mixing timescale on Jupiter was faster than the chemical equilibrium timescale, allowing carbon monoxide to be brought up high in the atmosphere.

Looking at this same process in brown dwarfs, Marley introduced Gliese 229B, the first unequivocal brown dwarf to be discovered. Gliese 229B is warmer than Jupiter but still quite cool, and it too has carbon monoxide in its atmosphere despite equilibrium chemistry saying it shouldn’t be there. Looking at a larger sample of brown dwarfs, researchers have mapped the presence of carbon monoxide as a function of effective temperature, using this relationship to understand how fast the atmospheres of these worlds are mixing as a function of temperature. This revealed changes in the depth of the convective boundary with temperature.

Moving to the second topic, Marley discussed some of the efforts to model clouds on brown dwarfs. Researchers have found that cloudy models are necessary to match observations for brown dwarfs with temperatures above about 1400K. At 1300K and below, cloudless models start to match better. Across just 100K, something is going on with clouds in brown dwarf atmospheres, but what? The answer appears to involve the interaction between global atmospheric dynamics and the clouds, producing holes in the clouds similar to those seen on Jupiter. This transition appears to have an impact on how brown dwarfs cool over time, causing a pileup of brown dwarfs with temperatures around 1300K.

Marley briefly touched on the final topic by noting that brown dwarfs appear to have temperature inversions (a localized reversal of the trend of decreasing atmospheric temperature with increasing altitude), but without nearby stars to heat their upper atmospheres, it’s not clear why. A student of Marley’s is working to understand the source of brown dwarfs’ temperature inversions.

Marley concluded by reemphasizing that many processes have been discovered and explored in planetary atmospheres before being applied to exoplanet and brown dwarf atmospheres. Because of this connection between planetary science and substellar astrophysics, there are ample opportunities for human connections as well, bringing together planetary scientists and astronomers to advance our understanding of distant worlds.

Return to Table of Contents.