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Circumplanetary disk

A circumplanetary disk (CPD) is a rotating disk of gas and encircling a , serving as a site for the formation of moons through the accretion of material, much like s around facilitate formation. These disks typically form around young giant s during the late stages of formation, when the accretes gas from the surrounding , creating a subdisk with sufficient to become rotationally supported. CPDs can arise through two primary mechanisms: core accretion, where a solid core grows by capturing gas and forms a hot, optically with masses around 0.1–1% of the 's mass, or gravitational instability, which produces cooler disks (temperatures below 100 K) that may be up to 8 times more massive relative to the . The properties of CPDs vary with the planet's mass and the circumstellar disk's aspect ratio; higher planet masses (e.g., several masses) and lower disk scale heights promote well-defined, thin disks, while lower masses lead to more envelope-like structures. In our , CPDs are hypothesized to have formed the and Saturn, with models suggesting they were fed by gas from the primordial nebula. Observationally, CPDs are rare and challenging to detect due to their small size and the prevalence of at large orbital radii where disk formation is less likely, but the first clear came in 2021 from observations of a disk around the PDS 70c, a -like world about 5.1 billion kilometers from its , with a disk roughly equal to 1 and mass sufficient to form up to three Moon-sized moons. Subsequent studies, including a 2025 analysis, confirm their scarcity at wide orbits but highlight potential detections around systems like AB Aur b, underscoring CPDs' role in testing theories of satellite formation and evolution.

Definition and Properties

Physical Characteristics

A circumplanetary disk is a -, -, or ring-shaped structure of gas, , planetesimals, and rocky material that orbits a forming , distinct from the larger circumstellar disk surrounding the central star. These disks arise from material accreted onto the planet, forming a rotationally supported subdisk embedded within the planet's . Unlike circumstellar disks, which span tens to hundreds of astronomical units, circumplanetary disks are confined to scales much smaller than the planet's orbital radius around the star. The radial extent of a circumplanetary disk typically begins at an inner edge just beyond the planet's radius, around 2 planetary radii, and extends outward to approximately 0.4–0.5 times the planet's Hill radius, where tidal forces from the star truncate the disk. For a Jupiter-mass planet at 5 au, the Hill radius is about 50 Jupiter radii, so the disk spans roughly 2 to 20–25 Jupiter radii. Mass estimates for these disks range from $10^{-5} to $10^{-3} times the planet's mass, though simulations show values up to $4 \times 10^{-2} M_p for more massive planets (5–10 M_\mathrm{Jup}), with the disk primarily composed of hydrogen and helium gas containing embedded dust grains from micron to centimeter sizes. The temperature profile decreases radially from around 1000 K near the inner edge, driven by viscous heating and stellar irradiation, to about 100 K at the outer edge, ensuring the entire disk remains above the water freezing point in many models but allowing for volatile condensation farther out. Recent JWST observations of systems like Delorme 1 AB b (2025) reveal carbon-rich disks with blackbody temperatures around 295 K, effective radii of approximately 19 R_Jup, and low gas masses on the order of 10^{-6} M_Jup, aligning with theoretical expectations for young, accreting CPDs. Key structural parameters include an aspect ratio H/r of approximately 0.1–0.3, reflecting the disk's moderate flaring due to thermal support, and a turbulent viscosity parameterized by \alpha \sim 10^{-3} to $10^{-2}, which governs angular momentum transport and accretion rates. Disk stability is maintained via the Toomre parameter Q > 1, typically Q \gg 1 in the inner regions and approaching 1 at the outer edge to prevent gravitational fragmentation. Compositionally, the disks are gas-dominated with a dust-to-gas mass ratio of about 0.01, though midplane depletion to $10^{-3}–$10^{-4} enhances ice formation; ice lines for water and other volatiles occur at 5–10 planetary radii (or 0.05–0.1 Hill radii), where temperatures drop below 150–180 K, enabling condensation of ices that influence moon compositions.

Role in Satellite Formation

Circumplanetary disks primarily function as nurseries for the formation of satellites, where planetesimals and particles coalesce through processes such as or core accretion to produce . In these disks, solid materials aggregate into larger bodies, with the disk's gaseous environment facilitating the capture and growth of these precursors to . A key mechanism within circumplanetary disks is pebble accretion, wherein centimeter- to meter-sized pebbles drift inward and accrete onto moon embryos, enabling rapid growth. This process allows protosatellites to form moon embryos on timescales of $10^4 to $10^5 years for large , outpacing gas dissipation in the disk. Additionally, remnants of the disk or material from disrupted satellites can coalesce into ring systems, preserving circumplanetary debris as observed in planetary ring structures. The disks influence satellite architecture through dynamical interactions, including inward migration driven by type I and type II torques between satellites and the disk gas, which can lead to resonant chains in satellite systems. In the gas-starved disk paradigm, the limited and time-variable supply of gas from the parent restricts satellite growth primarily to rocky or icy compositions, preventing the formation of moons. This paradigm favors the accretion of solids over extended periods, aligning with the compositions of known regular satellites. Moons formed in water-rich regions of circumplanetary disks, influenced by temperature gradients that position lines, hold implications for through the potential development of subsurface oceans. These oceans may arise from incorporated volatiles and subsequent , creating environments conducive to liquid persistence.

Theoretical Models

Formation Mechanisms

The primary mechanism for the formation of circumplanetary disks (CPDs) involves the transfer of from infalling circumstellar material during the accretion phase of a , leading to rotational instability that sheds material into a disk. This process partitions the incoming gas between direct accretion onto the planet and disk formation, with the disk emerging as excess cannot be fully absorbed by the planet's spin. In the core accretion model, a planetary core captures gas from the protoplanetary disk (PPD), and the shedding of excess angular momentum results in CPD formation. As the planet contracts during this phase, the transition from a spherical envelope to a rotationally supported disk occurs, driven by the inflow's specific angular momentum bias relative to the Hill sphere. Theoretical models predict distinct properties for CPDs formed via different mechanisms. In the core accretion scenario, CPDs are hot and optically thick, with masses typically 0.1–1% of the planet's mass. In contrast, the gravitational instability model involves rapid collapse of gas clumps in the PPD to form the planet, potentially producing cooler disks (temperatures below 100 K) that may be up to 8 times more massive relative to the planet. Bondi-Hoyle-Lyttleton accretion contributes by capturing ambient gas onto the moving planet, with the accretion rate given by \dot{M} \propto \frac{(G M_p)^2 \rho}{v^3}, where \rho is the and v is the . This influences the inflow pattern into the Hill sphere, enhancing disk buildup through Bondi radius effects. CPD formation typically occurs within $10^3 to $10^4 years after the planet reaches approximately 10 masses, aligning with the viscous spreading timescale during the initial contraction. The depends strongly on PPD properties, such that higher disk aspect ratios (H/r > 0.05) promote denser CPDs by facilitating more efficient mass delivery and transport into the Hill sphere.

Evolutionary Dynamics

Circumplanetary disks undergo viscous spreading after their initial formation, during which transport causes the disk to expand radially outward while facilitating inward accretion of gas onto the central . This is governed by the viscous for accretion disks, \frac{\partial \Sigma}{\partial t} = \frac{3}{r} \frac{\partial}{\partial r} \left[ r^{1/2} \frac{\partial}{\partial r} (\nu \Sigma r^{1/2}) \right], where \Sigma(r,t) is the surface density profile and \nu is the kinematic viscosity, typically parameterized in the \alpha-prescription as \nu = \alpha c_s H, with \alpha \sim 10^{-3}--$10^{-2}, sound speed c_s, and scale height H. In circumplanetary disks, this spreading limits the disk extent to roughly 0.3--0.5 times the planet's Hill radius, preventing excessive mass buildup and enabling efficient satellite formation within the inner regions. Simulations show that higher viscosity accelerates outward expansion, reducing the disk's inner density and altering the torque balance on embedded bodies. External from the host drives photoevaporation in circumplanetary disks, eroding the outer disk edge through heating and hydrodynamic that remove gas at rates scaling with the stellar . This significantly shortens the disk lifetime, typically to 10^4--10^5 years for Jupiter-mass planets in solar-type systems, though the overall evolutionary phase aligns with the dispersal over 1--10 Myr. Photoevaporation truncates the disk at radii where the ionization front balances viscous inflow, with mass-loss rates of \dot{M} \sim 10^{-10}--$10^{-8} M_\odot yr^{-1} for far- of 10^3--10^4 G_0. In clustered environments, intracluster can enhance dispersal, explaining architectural differences in satellite systems like those of and Saturn. Embedded moons in circumplanetary disks experience Type I driven by gravitational torques from Lindblad resonances, where density waves excited at orbital commensurabilities with the disk lead to net inward or outward drift depending on the torque imbalance. These torques can truncate the disk at approximately 0.5 times the Hill radius by clearing material through resonant interactions, limiting further outward spreading. Migration timescales for moonlets of 10^{-4}--10^{-2} masses range from 10^3--10^5 years, slower than viscous evolution in low-\alpha disks, allowing moons to accrete before falling onto the planet. The disk mass is constrained by tidal truncation within the Hill sphere, typically limited to about 0.01 times the planet's mass to prevent overflow and , as excess material would or accrete rapidly. This limit arises from the balance between viscous supply and tidal removal, with simulations showing steady-state masses of M_\mathrm{disk} \sim 10^{-3}--$10^{-2} M_p) for \alpha \sim 10^{-2}. Beyond this threshold, the disk destabilizes, ejecting gas and altering moon formation efficiency. Following gas dissipation via and photoevaporation, circumplanetary disks transition to debris disks composed of planetesimals, , and remnant on timescales of around 10 , mirroring the dispersal of the parent . This phase features collisional evolution of solid material, forming structures like narrow or belts analogous to Saturn's system, with replenished by impacts over 10^6--10^7 years. The gas-poor remnants provide long-term reservoirs for irregular satellites or ring maintenance.

Hypothetical Evidence in the Solar System

Jupiter's Early Disk

A circumplanetary disk around is hypothesized to have formed approximately 4.5 billion years ago, during the planet's rapid accretion phase within the solar nebula, when grew to its current mass of about 1 M_Jup. This disk arose from material shed via transport as contracted under its own gravity, with an estimated initial mass on the order of 10^{-3} M_Jup, sufficient to supply the building blocks for its satellite system. The disk's formation occurred over a short timescale of roughly 10^4 years during the planet's Kelvin-Helmholtz contraction, transitioning from a rotationally supported structure to a viscously evolving gaseous disk fed by inflow from the surrounding solar nebula. Model-based evidence for this early disk draws heavily from the characteristics of Jupiter's Galilean moons—Io, Europa, Ganymede, and Callisto—which exhibit a clear compositional gradient: the inner moons (Io and Europa) are predominantly rocky with low ice fractions, while the outer ones (Ganymede and Callisto) are increasingly icy. This gradient is explained by the presence of a snow line in the disk at approximately 15 R_Jup (Jupiter radii), beyond which water ice could condense and incorporate into accreting satellites, while inner regions remained warmer and drier. Simulations indicate the disk extended outward to about 50 R_Jup, limited by tidal truncation near Jupiter's Hill sphere, with moon formation occurring via pebble accretion processes that assembled the satellites in as little as 10^5 years. Seminal models by Canup and Ward (2002, updated in 2010) demonstrate how angular momentum shedding during Jupiter's spin-down phase populated the disk, enabling efficient satellite growth through the capture and coagulation of solid pebbles drifting inward. Although no direct observational evidence exists for this ancient disk, its influence is inferred from the current orbital architecture of the , particularly the Laplace resonance among , , and (with mean motion ratios of 4:2:1), which models suggest was shaped by differential torques from the dissipating disk on migrating satellites. Possible remnants include Jupiter's faint , potentially originating from disrupted disk material or collisions involving small moons, as dust particles ejected by impacts on inner satellites like Amalthea could trace back to primordial debris. Compositional analyses further support a shared disk origin, with the moons' bulk densities and ice fractions aligning with accretion from a common reservoir where volatiles sublimated in the inner disk but preserved outward, consistent with isotopic and elemental similarities indicative of nebular processing.

Saturn's Early Disk

During Saturn's formation approximately 4.5 billion years ago, a circumplanetary disk of gas and solids is inferred to have surrounded the planet, with an estimated mass of about 10^{-3} M_{Sat} and extending outward to roughly 100 R_{Sat}. This disk provided the material reservoir for the accretion of Saturn's regular satellites, with its structure influenced by the planet's rapid growth phase within the solar nebula. Evidence for this early disk is drawn from the formation histories of Saturn's moons, particularly , which likely accreted via pebble accretion in the cooler outer regions beyond approximately 20 R_{Sat}. Smaller moons such as are thought to have originated from remnants of this disk material, accreting as the disk viscously evolved and spread. The high content in both the rings and moons, exceeding 90% in many cases, points to a disk located around 20 R_{Sat}, where temperatures allowed to condense and dominate the composition. The current is interpreted as a dilute remnant of this massive disk, which underwent disruption through formation processes or external impacts, leaving behind the observed icy structure. Models by Charnoz et al. (2011) propose that the initial ring mass was approximately 10^{-3} M_{Sat}, sufficient to accrete the mid-sized moons like , , Tethys, Dione, and as the disk spread viscously outward. Dynamical simulations indicate that interactions between the evolving disk and drove orbital migrations, leading to the current alignment of Tethys, Dione, and through capture into mean-motion resonances such as the 2:1 -Dione configuration. Data from the Cassini mission, including measurements of satellite orbital parameters, provide constraints on past disk interactions, with observed tidal migration rates implying prior viscous torques from a denser disk that influenced early and resonance locking. These interactions highlight the disk's role in shaping the system's before its left the enduring ring-moon configuration.

Observed Exoplanet Candidates

PDS 70 System

The PDS 70 system is a young centered on a of spectral type K7, with an age of approximately 5–6 million years and a distance of about 370 light-years from . The star hosts a featuring prominent gaps cleared by two forming giant s, PDS 70 b and PDS 70 c, which were directly imaged in the near-infrared using high-contrast instruments such as on the (VLT) and GPI. These planets, embedded within the disk's cavities, provide a unique laboratory for studying ongoing planet and formation processes. PDS 70 b, a Jupiter-mass (approximately 2–8 M_Jup) orbiting at about 22 AU from the star, was the site of the first submillimeter detection of potential circumplanetary disk material in using observations at 855 μm. The emission source, offset by 0.074 arcsec from the planet, exhibited a flux of 73–100 μJy beam⁻¹, corresponding to a mass of roughly 1.8–3.2 × 10⁻³ M_⊕ for optically thin 1 mm grains at 20 K, or up to four times higher if marginally optically thick. Assuming a standard gas-to-dust ratio of 100, the total disk mass could reach ~0.001 M_Jup, with a compact size limited to ≲4 AU (about 0.2 R_Hill, where R_Hill is the planet's Hill radius). This dust emission is brighter than that around PDS 70 c, suggesting a dust-rich environment potentially conducive to moon formation, though its exact association with a circumplanetary disk remains tentative due to the offset. PDS 70 c, a more massive (1–10 M_Jup) at ~34 AU, hosts the clearest evidence of a circumplanetary disk, confirmed through both continuum and molecular gas observations. In 2019 data at 855 μm, a spatially unresolved source was detected with a flux of 106 ± 19 μJy beam⁻¹, yielding a of 2–4.2 × 10⁻³ M_⊕ and a size ≲4 AU (~0.1–0.2 R_Hill). Higher-resolution in refined this to a compact disk with radius <1.2 AU, ~0.007–0.031 M_⊕ (depending on grain size), and temperature ~26 K, consistent with viscous heating and irradiation models. The first gaseous detection came in 2022 via Band 6 observations of ¹²CO and ¹³CO J=2–1 lines, revealing a point-source emission in ¹³CO with integrated intensity 2.54 mJy beam⁻¹ km s⁻¹, gas temperature ≥35 K, and ≥0.095 M_Jup—confirming an active, gaseous circumplanetary disk as a moon-forming site. This gas emission, warmer and more localized than the surrounding material, indicates ongoing accretion. These circumplanetary disks are embedded within the parental of , with no spatial overlap between their substructures; b's emission is dust-dominated and fainter in gas, while c's shows stronger gas signatures. Millimeter with has been crucial for resolving these features at ~0.1 arcsec scales, complementing near-infrared high-contrast imaging that confirms the planets' positions and accretion activity. The detections align with theoretical expectations for circumplanetary disk formation via gravitational capture from the circumstellar disk, providing direct evidence for satellite formation mechanisms in exoplanetary systems.

Recent Discoveries

In September 2025, NASA's (JWST) detected a moon-forming circumplanetary disk around the young CT Cha b using its (MIRI) for . CT Cha b, with an estimated mass of 10-15 masses, orbits its star at an angular separation of approximately 1.3 arcseconds, located about 625 light-years away. The disk, rich in carbon-bearing molecules, extends to roughly 0.3 times the planet's Hill radius and shows potential for forming icy moons through ongoing dust and gas processes. This observation marks one of the clearest views of a cooler, outer disk region, highlighting JWST's sensitivity to such structures. In June 2025, JWST observations of the YSES-1 system revealed clouds in the atmosphere of the inner YSES-1 c and signatures of a circumplanetary disk around the outer YSES-1 b, orbiting a young solar-type star about 300 light-years distant. These findings, based on mid-infrared , indicate active disk accretion feeding material into the 's envelope, with the disk potentially enabling formation through silicate-rich debris. The dual- setup provides a snapshot of differing evolutionary stages, where the inner disk shows atmospheric interactions akin to haze formation. A November 2025 report detailed a candidate circumplanetary disk in the ASASSN-24fw system, identified through a transient 4-magnitude dip in the light curve of a main-sequence approximately 1,000 parsecs away. The , lasting about 8 months from late 2024, suggests an by a gas-rich disk with an estimated of around 0.01 times that of its host substellar companion, possibly resulting from a planetary collision or debris accumulation. Follow-up photometry and data support the disk's optically thick nature, distinguishing it from stellar variability. By late 2025, JWST's infrared capabilities have enabled the detection of cooler, carbon- and silicate-rich disks, with follow-up observations from TESS and confirming around five circumplanetary disk candidates overall. These advancements build on earlier foundational observations like those of , shifting focus to diverse chemical compositions and accretion dynamics. Key challenges in identifying these disks include differentiating circumplanetary from extended planetary atmospheres and their rarity at large orbital radii beyond 50 , where disk stability diminishes due to tidal influences. Future prospects involve (ELT) observations targeting transitional systems like , aiming to resolve finer disk structures and gas kinematics with mid-infrared spectrographs such as .

References

  1. [1]
    Astronomers make first clear detection of a moon-forming disc ... - ESO
    Jul 22, 2021 · The disc in question, called a circumplanetary disc, surrounds the exoplanet PDS 70c, one of two giant, Jupiter-like planets orbiting a star ...<|control11|><|separator|>
  2. [2]
    Circumplanetary Disks are Rare Around Planets at Large Orbital Radii
    Jul 9, 2025 · Circumplanetary disks (CPDs) are a possible byproduct of the postrunaway phase of giant planet formation (J. B. Pollack et al. 1996), when the ...
  3. [3]
    Circumplanetary discs around young giant planets - Oxford Academic
    Circumplanetary discs can be found around forming giant planets, regardless of whether core accretion or gravitational instability built the planet. We carried ...
  4. [4]
  5. [5]
  6. [6]
  7. [7]
    None
    ### Temperature Profiles and Effects on Disk Properties
  8. [8]
    Accretion in giant planet circumplanetary discs - Oxford Academic
    ... aspect ratio, H/r (centre-left panel), Toomre's Q (centre-right panel), and viscosity parameter α (bottom-left panel) for five circumplanetary disc models.Missing: disk | Show results with:disk
  9. [9]
    Circumplanetary disk ices - Astronomy & Astrophysics
    2D dust temperature distribution around the circumstellar disk gap in the range 40–120 K (top). Solid, dashed, and dotted black con- tours indicate the ...
  10. [10]
    Dust Evolution and Satellitesimal Formation in Circumplanetary Disks
    Oct 23, 2018 · It is believed that satellites of giant planets form in circumplanetary disks (CPDs). Many of the previous contributions assumed that their ...Missing: seminal | Show results with:seminal
  11. [11]
    Formation of moon systems around giant planets
    The pebble-accreting protosatellites rapidly migrate inward and pile up in resonant chains at the inner edge of the circum-planetary disk. We propose that ...
  12. [12]
    11 Question 8: Circumplanetary Systems | Origins, Worlds, and Life
    The regular ring–moon systems of the giant planets (i.e., the rings and moons orbiting in or near the planet's equatorial plane) probably originated from a disk ...
  13. [13]
    Growth and evolution of satellites in a Jovian massive disc
    In this model, the first generation of satellites forms and performs a type I migration through the disc, then a second generation of satellites forms and ...
  14. [14]
    Formation, Habitability, and Detection of Extrasolar Moons
    Most notably, we show that natural satellites in the range of 0.1–0.5 Earth mass (i) are potentially habitable, (ii) can form within the circumplanetary debris ...
  15. [15]
    Circumplanetary disk ices - II. Composition - Astronomy & Astrophysics
    The subsurface oceans of icy satellites are among the most compelling among the potentially habitable environments in our Solar System. The question of ...
  16. [16]
    CIRCUMPLANETARY DISK FORMATION - IOPscience
    Oct 1, 2010 · ... angular momentum budget than in the inviscid case. A circumplanetary disk also shares basic traits with the circumsolar disk, in which ...
  17. [17]
    [PDF] The effects of viscosity on circumplanetary disks
    Thus, viscosity can slow the migration speed of a protoplanet. After including viscosity, the size of the circumplanetary disk can be decreased by a factor.Missing: aspect Toomre
  18. [18]
    Photoevaporation of the Jovian circumplanetary disk
    Previously, a rapid dispersal of the Jovian CPD has been invoked to explain the difference in the architectures between the Jovian and Saturnian regular ...
  19. [19]
    PHOTOEVAPORATION AS A TRUNCATION MECHANISM FOR ...
    We also find that photoevaporation can successfully act as a clearing mechanism for circumplanetary nebulae on the potentially short timescales, 102–104 yr, ...
  20. [20]
    Tidal Truncation of Circumplanetary Disks Fails above a Critical Disk ...
    We find that the most significant dependence of the truncation boundary is on the disk aspect ratio H/R. Circumplanetary disks are efficiently truncated for H/R ...Missing: M_p | Show results with:M_p
  21. [21]
    Insights into Planet Formation from Debris Disks
    Mar 22, 2016 · Such disks last for up to around 10 Myr before dispersing through mechanisms that are still debated, leaving a planetary system and a debris ...
  22. [22]
    The dynamical role of the circumplanetary disc in planetary migration
    Jun 4, 2009 · Adding the mass of the CPD to the perturbing mass of the planet accelerates the migration. Excluding a part of the Hill sphere is a very touchy ...Missing: disk | Show results with:disk
  23. [23]
    Massive Retrograde Moons May Survive During Different Hot ... - arXiv
    Sep 16, 2025 · As the gas giant migrates inward, its reduced Hill Sphere will shrink. However, the planet remains puffy since the timescale of disk migration ...
  24. [24]
    Formation of the Galilean Satellites: Conditions of Accretion
    We examine formation conditions for the Galilean satellites in the context of models of late-stage giant planet accretion and satellite-disk interactions.
  25. [25]
    Saturn's Formation and Early Evolution at the Origin of Jupiter's ...
    The four massive Galilean satellites are believed to have formed within a circumplanetary disk during the last stages of Jupiter's formation.
  26. [26]
    Galileo Finds Jupiter's Rings Formed by Dust Blasted Off Small Moons
    Sep 15, 1998 · Jupiter's intricate, swirling ring system is formed by dust kicked up as interplanetary meteoroids smash into the giant planet's four small ...Missing: origin disrupted material
  27. [27]
    (PDF) Understanding the Formation of Saturn's Regular Moons in ...
    Aug 9, 2025 · The regular satellites of the giant planets are believed to have finished their accretion concurrent with the planets, about 4.5 Gyr ago. A ...Missing: R_Sat | Show results with:R_Sat
  28. [28]
    Accretion of Saturn's Inner Mid-sized Moons from a Massive ...
    Feb 13, 2017 · The former was advocated in Charnoz et al. (2011); we pursue the latter possibility here. In this paper, we simulate the viscous evolution of a ...
  29. [29]
    Orbital evolution of Saturn's satellites due to the interaction between ...
    Crida & Charnoz (2012) suggested that the satellite-disk (rings) interaction is more effective for the orbital migration than Saturn's tide until the satellite ...
  30. [30]
    Formation Conditions of Titan's and Enceladus's Building Blocks in ...
    Mar 12, 2021 · The building blocks of Titan and Enceladus are believed to have formed in a late-stage circumplanetary disk (CPD) around Saturn.
  31. [31]
    On the Location of the Snow Line in a Protoplanetary Disk
    In a protoplanetary disk, the inner edge of the region where the temperature falls below the condensation temperature of water is referred to as the snow line.Missing: circumplanetary | Show results with:circumplanetary
  32. [32]
    Accretion of Saturn's mid-sized moons during the viscous spreading ...
    The resulting asymptotic value of the disk's mass would be about Mimas' mass (as predicted by the analytical calculation of Salmon et al., 2010; see their Eqs.
  33. [33]
    Formation of the Cassini Division – I. Shaping the rings by Mimas ...
    The density evolution relies on a viscosity model that considers three different viscous sources as described in Salmon et al. (2010):. a translational or ' ...Missing: disk | Show results with:disk
  34. [34]
    Detection of Continuum Submillimeter Emission Associated with ...
    However, the offset between PDS 70 b and PDS 70 bsmm shows that ALMA observations alone might not be sufficient to identify planets in the act of forming. As ...Abstract · Introduction · Data Analysis · Discussion
  35. [35]
    A Circumplanetary Disk around PDS70c - IOPscience
    Jul 22, 2021 · PDS 70 is a unique system in which two protoplanets, PDS 70 b and c, have been discovered within the dust-depleted cavity of their disk.Introduction · Discussion · Conclusions · Appendix A: ALMA...
  36. [36]
    NASA's Webb Telescope Studies Moon-Forming Disk Around ...
    Sep 29, 2025 · A circumplanetary disk has long been hypothesized as the birthplace of Jupiter's four major moons. These Galilean satellites must have condensed ...Missing: inward migration compresses
  37. [37]
    Webb Discovers Exomoon-Forming Circumplanetary Disk around ...
    Sep 29, 2025 · Astronomers using the NASA/ESA/CSA James Webb Space Telescope have found the carbon-rich disk surrounding CT Cha b, a giant exoplanet around ...
  38. [38]
    Webb studies moon-forming disc around massive planet - ESA
    Sep 29, 2025 · A circumplanetary disc of debris has long been hypothesised as the birthplace of Jupiter's four major moons. These Galilean satellites must have ...Missing: inward migration compresses
  39. [39]
    Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet ...
    Jun 10, 2025 · Based on the combined forward modelling and retrieval analysis, we find an effective temperature range of 950–1,100 K and a surface gravity ...
  40. [40]
    Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet ...
    Jul 25, 2025 · The study reports the first direct observations of silicate clouds in YSES-1 c and a circumplanetary disk silicate emission around YSES-1 b. ...
  41. [41]
    Webb Observes Two Young Exoplanets in YSES-1 System - Sci.News
    Jun 11, 2025 · Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet system. Nature, published online June 10, 2025; doi: 10.1038/s41586-025-09174 ...
  42. [42]
    Candidate circumplanetary disk occultation of a main-sequence star
    Jul 7, 2025 · ASASSN-24fw is a 4-magnitude dimming event of a star, likely caused by a gas-rich circumplanetary disk, possibly from a planetary collision.Missing: Ab | Show results with:Ab
  43. [43]
    Planet ASASSN-24fw Ab
    Nov 5, 2025 · (2025): A circumplanetary disk as large as 0.7 AUs surrounds the substellar occulter. ... ASASSN-24fw: Candidate circumplanetary disk ...
  44. [44]
    Silicate Clouds Discovered In The Atmosphere Of Exoplanet YSES-1 b
    Jun 12, 2025 · The presence of silicate clouds in one of the planet's atmospheres, and a circumplanetary disk thought to feed material that can form moons around the other.<|control11|><|separator|>
  45. [45]
  46. [46]
    Observing circumplanetary disks with METIS
    From the maximum possible elevation of HD 100546 and altitude of the ELT, we adopted an airmass of 1.5 for observing parameters. The atmospheric conditions are ...