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Lava planet

A lava planet is a rocky exoplanet, typically Earth-sized or a super-Earth, that orbits extremely close to its host star, resulting in intense stellar radiation that maintains a global or hemispheric magma ocean on its surface.^[1] These planets are often tidally locked, with one side perpetually facing the star and experiencing daytime temperatures of 2,000 to 4,000 Kelvin (approximately 1,727 to 3,727°C), sufficient to melt and even vaporize silicate rocks, while the night side is significantly cooler, often below 200 K in models without atmospheric heat redistribution.^[2]^[1] The formation of lava planets is tied to their close-in orbits, which prevent the surface from solidifying despite their rocky, Earth-like density, leading to shallow magma oceans that can persist for billions of years on the dayside.^[1] Vaporized rock from the intense heat creates silicate-rich atmospheres, potentially observable through spectral signatures of elements like magnesium, iron, and calcium, which provide insights into the planet's interior composition.^[2] Over time, crystals may form at the edges of cooling magma pools, altering the chemical makeup and enabling age estimates via atmospheric analysis.^[1] Notable examples include CoRoT-7b, the first confirmed rocky exoplanet discovered in 2009, which orbits its K-type star every 20 hours at a distance of just 0.017 AU, with surface temperatures hot enough for lava oceans or even boiling rock rains.^[3]^[4] Another candidate is 55 Cancri e, a super-Earth with a dayside potentially covered in molten lava due to its ultra-short 18-hour orbit around a Sun-like star.^[1] Detailed thermal mapping of 55 Cancri e in 2016 revealed a dayside temperature of around 2,500 K with cooler evening and morning regions, suggesting extensive lava coverage.^[5] Lava planets represent a frontier in exoplanet science, offering clues to planetary formation, migration, and differentiation processes, as their molten states expose internal structures that solid worlds conceal.^[2] Recent studies as of 2024 have confirmed a secondary atmosphere on 55 Cancri e likely sourced from its magma ocean, while 2025 models detail long-term evolutionary processes.^[6]^[7] Observations with telescopes like the James Webb Space Telescope (JWST) are poised to detect their unique atmospheres, refining models of how rocky worlds evolve in close stellar environments.^[1]

Definition and Characteristics

Definition

A lava planet, also referred to as a lava world, is a hypothetical type of terrestrial exoplanet characterized by a surface that is entirely or mostly covered by molten silicate rock in the form of persistent oceans, seas, or pools of lava. This extreme state arises from surface temperatures that reach or exceed the solidus point of rock, approximately 1300 K, either globally or across a significant hemisphere, often driven by intense stellar irradiation on ultra-short-period orbits.^[8] These planets are rocky in composition, with minimal or no substantial volatile atmospheres due to efficient erosion by extreme ultraviolet flux and stellar winds.^[9] Lava planets encompass Earth-sized worlds and super-Earths, typically with radii between 1 and 2 times that of Earth and masses up to 10 times Earth's mass.^[10] The concept of lava-ocean planets was first proposed in the scientific literature in 2011 by Léger et al., who analyzed the properties of the ultra-short-period exoplanet CoRoT-7b, a rocky super-Earth with conditions supporting molten surface features, with the term "lava planet" gaining usage in subsequent studies.^[9] What distinguishes lava planets from other hot rocky exoplanets is the maintenance of a persistent global or hemispheric magma ocean through continuous extreme heating, rather than transient molten regions limited to localized volcanism or impact events.^[8] Due to their proximity to host stars, these planets are often tidally locked, with one side perpetually facing the star and sustaining the lava ocean while the opposite side remains comparatively cold.^[9]

Physical Characteristics

Lava planets, also known as lava worlds, exhibit extreme surface temperatures typically exceeding 2000 K on their daysides due to intense stellar irradiation from their close orbits. These temperatures are sufficient to melt silicate rocks, resulting in a global or hemispheric ocean of molten lava that emits visible glow from thermal radiation. Recent observations with the James Webb Space Telescope (JWST), as of 2025, have detected atmospheres on candidates like 55 Cancri e and TOI-561 b, supporting the presence of rock vapor atmospheres and refining models of their thermal structures.^[11]^[12] The composition of lava planets is predominantly rocky, consisting of an iron-rich core and a silicate mantle, similar to terrestrial planets but with potential for elevated volatile content during their early formation phases. The core is often modeled as liquid iron or iron alloyed with oxygen, while the mantle comprises pyrolitic materials rich in magnesium, silicon, and iron oxides, such as olivine and pyroxenes. Early-stage volatiles, including water and carbon, can be incorporated into basal magma oceans at levels up to 130 times Earth's ocean mass for water and 1000 times for surface carbon, though much is lost over time due to high temperatures.^[13] Internally, lava planets feature a differentiated structure with a molten mantle that drives intense volcanism, potentially forming a new crust from partial melts. This includes configurations like a mantle magma ocean, a surface magma ocean, or a multi-layered setup with a solid rock interlayer between surface and basal oceans. A solid core may persist if partially cooled, but the dominant molten layers sustain extreme geological activity. Density estimates for these planets range from 4 to 7 g/cm³, higher than Earth's 5.5 g/cm³ owing to compression from tidal forces and iron enrichment. Due to their proximity to host stars, lava planets are synchronously rotating via tidal locking, with one hemisphere perpetually facing the star.

Formation and Evolution

Formation Mechanisms

Lava planets originate as rocky planetesimals that accrete in the inner regions of protoplanetary disks surrounding young stars, where high temperatures favor the condensation of refractory materials like silicates and metals.^[14] These planetesimals aggregate through pairwise collisions and gravitational instabilities, building up terrestrial-mass cores (typically 1–8 Earth masses) in environments rich in dust and gas.^[15] The inner disk's proximity to the star ensures rapid formation of these dense, iron-rich bodies, distinct from gas giants that form farther out.^[16] Inward migration is a key process that transports these rocky planets to ultra-short orbital periods (<1 day), often via interactions with the protoplanetary disk or dynamical instabilities. Disk-driven migration, including Type I torques for low-mass planets and Type II for more massive ones, can push cores from several AU to stellar distances of ~0.01 AU over the disk's lifetime.^[17] Alternatively, secular perturbations from outer companions, such as hot Jupiters, excite eccentricities that lead to tidal dissipation and orbital decay, enabling survival in close orbits.^[15] This migration places the planets in regions too hot for in-situ formation, resulting in stripped envelopes if they started as sub-Neptunes.^[2] During the high-energy accretion phase, giant impacts and gravitational energy release from rapid assembly generate substantial heat, melting the planetary mantle and initiating global magma oceans.^[14] Radionuclide decay in the core further contributes to internal heating, sustaining molten conditions even as accretion wanes.^[14] These processes establish the initial differentiated structure, with a molten silicate layer overlying a metallic core.^[16] Lava planets are more prevalent around M-dwarf stars due to their compact protoplanetary disks and closer-in habitable zones, which facilitate the retention of rocky bodies at short separations without excessive gas accretion.^[18] However, formation around G- and K-type stars is also possible, particularly through efficient migration mechanisms.^[15] The entire formation sequence, from planetesimal accretion to final orbital placement, typically occurs within 10–100 million years after the host star's formation, aligning with observed protoplanetary disk lifetimes.^[19] Post-migration, brief tidal interactions help circularize orbits but do not dominate the initial setup.^[15]

Evolutionary Processes

Following the formation of a lava planet, the initial phase features a global magma ocean that undergoes significant outgassing, releasing volatiles from the molten silicate mantle to form a thick atmosphere primarily composed of steam (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂).^[20] This outgassing occurs during the late stages of planetary growth, where chemical equilibration in the magma ocean drives the release of elements such as H, C, O, and S, resulting in atmospheric surface pressures ranging from tens to hundreds of bars, depending on the planet's mass and the depth of the molten layer.^[20] Under oxidized conditions, H₂O dominates the composition, while more reduced states favor H₂ alongside CO and SO₂.^[20] Cooling of the magma ocean primarily proceeds through radiative heat loss from the intensely irradiated dayside, where surface temperatures can exceed 2000 K, supplemented by atmospheric energy transport.^[21] On the nightside, where stellar insolation is absent, cooling is more efficient, potentially leading to the formation of a solid crust or even subsurface magma oceans if internal heat fluxes remain sufficient to prevent full solidification.^[21] Convection in the atmosphere, often limited by radiative processes in thick, volatile-rich envelopes, plays a key role in redistributing heat, though "convective shutdown" can occur in reducing atmospheres, stabilizing isothermal layers and slowing overall cooling. Recent models from 2025 highlight the asymmetric nature of lava planet evolution due to tidal locking, predicting persistent molten lava seas on the dayside—typically less than 200 km deep—maintained by ongoing stellar heating and solid-liquid fractionation that enriches the melt in iron oxide (FeO).^[22] In contrast, the nightside may develop a solid crust through rapid cooling and gravitational instability, with temperatures dropping to around 100 K in solid-dominated interiors, while the global magma ocean phase transitions to a "mushy" state within hundreds of millions of years.^[22] This dichotomy persists over billions of years, with the dayside atmosphere reflecting the bulk silicate composition and the nightside potentially locking volatiles like sodium (Na) and potassium (K) into surface features.^[22] The lifespan of the fully molten state varies from approximately 10⁶ to 10⁹ years, influenced by the host star's luminosity, the planet's mass, and internal tidal heating.^[21] Smaller planets (around 1 Earth radius) with lower core mass fractions solidify their nightside faster, within 500 million to 1.2 billion years, while larger ones (1.5 Earth radii) retain shallower dayside oceans longer due to higher gravity suppressing melt depth.^[21] Without additional heat sources like tidal dissipation, the nightside cools to form a stable crust, but the dayside magma persists indefinitely under constant insolation.^[21] A complete transition to a solid planet is theoretically possible if the orbit migrates outward, reducing stellar heating, but such scenarios are rare owing to dominant tidal decay that drives inward orbital evolution and sustains molten conditions.^[21] In typical cases, lava planets evolve into a hybrid state with a perpetual dayside ocean and stratified solid mantle, influencing long-term atmospheric and interior dynamics.

Orbital and Environmental Factors

Stellar Proximity and Insolation

Lava planets are characterized by their exceptionally close orbits to host stars, with semi-major axes typically less than 0.02 AU.^[23] This proximity results in ultra-short orbital periods of less than one Earth day, enabling the intense gravitational and radiative interactions that define these worlds.^[24] Such tight orbits position the planets within the inner reaches of their stellar systems, where the dominant energy input is stellar radiation rather than internal heat sources. The stellar insolation on lava planets far exceeds that on Earth, reaching levels 1,000 to 10,000 times greater due to the inverse square law dependence on distance.^[25] This flux is quantified by the formula F = \frac{L}{4\pi a^2}, where L is the stellar luminosity and a is the semi-major axis, highlighting how even modest reductions in orbital distance amplify the received energy dramatically.^[24] On the dayside, this extreme heating drives equilibrium temperatures of approximately 2000–3000 K, promoting thermal emission primarily in the infrared wavelengths as the planet re-radiates absorbed energy.^[8] Host star properties play a critical role in modulating insolation effects, with active young stars delivering elevated fluxes that accelerate atmospheric escape through enhanced photoevaporation.^[26] If the orbit approaches the Roche lobe radius, gravitational disruption can further promote mass loss, potentially stripping volatile envelopes and exposing the rocky core to even greater stellar influence.^[27] Due to this stellar proximity, lava planets are generally tidally locked, with one hemisphere perpetually facing the star.^[24]

Tidal Locking Effects

Tidal locking, or synchronous rotation, is a prevalent outcome for lava planets due to their close orbital proximity to host stars, resulting in the planet's rotational period matching its orbital period. This synchronization causes one hemisphere—the dayside—to perpetually face the star, while the opposite hemisphere—the nightside—remains in perpetual darkness. Consequently, this configuration generates an extreme temperature gradient across the planet's surface, with dayside temperatures often exceeding 2000 K, maintaining widespread molten lava oceans, and nightside temperatures around 1000–1500 K, potentially allowing limited solidification.^[24]^[28] The gravitational interactions responsible for tidal locking also induce permanent tidal bulges on the planet, deforming its shape and generating internal friction as the material responds to the varying gravitational pull. In lava planets, where the mantle and surface are partially or fully molten, this deformation leads to significant internal heating through tidal dissipation, supplementing the intense stellar insolation. This additional heat source can sustain or enhance mantle convection, contributing to the planet's overall thermal budget and influencing long-term evolution.^[29]^[30] Tidal stresses from this locked configuration further promote enhanced volcanic activity, driving widespread resurfacing through recurrent lava flows and eruptions. The differential stresses across the planet's interior, particularly at the substellar and antistellar points, facilitate magma upwelling and crustal disruption, leading to dynamic geological processes that redistribute surface materials globally. This tidal-driven volcanism is particularly pronounced in close-in rocky worlds, where it can dominate over radiogenic heating.^[30]^[31] Recent 2025 research highlights the nightside, or "dark side," of tidally locked lava planets as a region potentially conducive to the condensation of volatiles and the formation of a more rigid crust, contrasting the fluid dayside. Models indicate that if the planetary interior is sufficiently hot, heat transport to the nightside could prevent full atmospheric collapse, allowing volatiles like silicates or minor atmospheric components to condense and form solid features, providing insights into the planet's differentiation and thermal state.^[32] The timescale for achieving tidal locking in these systems is remarkably rapid for close orbits, typically occurring within 10^5 to 10^6 years, driven by the strong tidal torques from the nearby star. This quick synchronization ensures that most observed lava planet candidates are already in this state, shaping their observable properties from early in their lifetimes.^[33]

Atmosphere and Surface Features

Atmospheric Properties

The atmospheres of lava planets are primarily composed of rock vapors evaporated from the molten surface, including sodium (Na), potassium (K), oxygen (O), silicon monoxide (SiO), and other species such as O₂, iron (Fe), and silicon dioxide (SiO₂).^[34]^[35] These components arise due to the high temperatures exceeding the vaporization points of silicates on the dayside, creating a mineral-dominated envelope.^[36] In addition to these rock vapors, atmospheres may include outgassed volatiles like water vapor (H₂O) and carbon dioxide (CO₂) released from the planetary interior during magma ocean phases.^[36]^[37] These atmospheres form thick, high-pressure envelopes, with surface pressures typically ranging from 10 to 100 bar, depending on the balance between outgassing rates and escape processes.^[12]^[38] The envelopes can extend to significant altitudes, potentially hazy due to condensates of silicate particles that form clouds or aerosols, scattering light and altering thermal structures.^[39] Such haziness arises from the condensation of rock vapor species on the cooler nightside or upper layers. Atmospheric dynamics on lava planets feature strong winds, often super-rotating due to the planet's tidal locking and intense dayside heating, which drive eastward jets that transfer heat toward the nightside.^[40]^[41] These winds facilitate global heat redistribution, mitigating extreme temperature contrasts between day and night hemispheres. Retention of these atmospheres faces challenges from intense ultraviolet (UV) and X-ray irradiation from the close-orbiting host star, promoting hydrodynamic escape where outward flows strip lighter components and contribute to atmospheric loss.^[42]^[43] Despite this, massive atmospheres with sufficient outgassing can persist over billions of years, particularly if hydrogen or other volatiles buffer the escape.^[35] Observationally, these atmospheres are detectable via transmission spectroscopy during planetary transits, revealing absorption features from metal vapors such as Na, K, and SiO in the optical and near-infrared.^[44]^[45] Such signatures provide key evidence for rock vapor dominance, distinguishing lava planets from other hot rocky worlds.^[46]

Geological Surface

Lava planets exhibit global magma oceans that dominate their geological surfaces, typically extending to depths of 10-100 km in models of partially molten mantles, though deeper hemispherical oceans reaching the core-mantle boundary have been proposed for intensely heated daysides.^[47] These oceans consist of vigorously convecting molten rock, where heat from stellar irradiation and internal processes drives large-scale circulation, potentially generating plate tectonics-like activity through crustal recycling and mantle upwelling.^[48]^[49] The surface is characterized by vast lava plains formed by widespread effusive volcanism, creating roiling seas of molten material on the dayside, with temperatures exceeding 2000 K preventing stable crust formation.^[50] Resurfacing occurs continuously due to tidal heating, which sustains high heat fluxes and promotes frequent eruptions, effectively renewing the surface on short geological timescales and inhibiting long-term topographic features on the illuminated hemisphere. Mineralogically, the lavas are predominantly basalt-like, composed of silicate melts rich in SiO₂, MgO, and FeO, while deeper layers may incorporate high-pressure phases such as perovskite under extreme conditions.^[51]^[52] Recent 2025 models highlight asymmetric geology, with persistent dayside magma oceans overlain by vapor atmospheres in younger planets, contrasting with cooler, solidifying nightside regions that form dynamic highlands through solidification and potential volatile outgassing.^[53] In older lava planets, the dayside retains shallow molten oceans, while the nightside develops a mostly solid crust, influenced by heat transport and tidal stresses that exacerbate hemispherical differences.^[54] This asymmetry arises from tidal locking, where dayside insolation maintains liquidity, and nightside cooling fosters crustal buildup over billions of years.^[55]

Detection and Candidates

Observational Methods

Observational methods for lava planets, which are ultra-short-period rocky exoplanets with extreme stellar irradiation leading to molten surfaces, primarily rely on indirect techniques due to their small sizes and proximity to host stars. These methods leverage space-based telescopes to overcome atmospheric interference and detect faint signals from planets typically smaller than Earth orbiting in periods of hours to days. Key approaches include transit photometry for initial discovery, radial velocity measurements for mass determination, and infrared spectroscopy for characterizing thermal emissions. Transit photometry detects lava planet candidates by observing periodic dips in a star's brightness as the planet passes in front of it, revealing short-period orbits conducive to high insolation. Missions like the Transiting Exoplanet Survey Satellite (TESS) have identified numerous ultra-short-period rocky planets through high-precision light curves, enabling the detection of transits as shallow as 0.1% for Earth-sized objects around bright stars. The James Webb Space Telescope (JWST) builds on this by providing follow-up observations in multiple wavelengths to confirm and refine orbital parameters, particularly for candidates in the habitable zone of M-dwarfs or closer-in systems.^[56] Radial velocity measurements complement transits by quantifying the star's wobble due to the planet's gravitational pull, allowing estimation of the planet's mass and thus bulk density to infer rocky compositions. For close-in rocky exoplanets, high-precision spectrographs like HARPS-N on ground-based telescopes or ESPRESSO achieve the necessary sub-meter-per-second precision to measure masses of planets as small as 1-5 Earth masses, despite challenges from stellar activity in active host stars. This method has been crucial for confirming the terrestrial nature of potential lava world candidates, such as early detections around solar-type stars.^[57]^[8] Emission spectroscopy in the infrared targets the thermal glow from a lava planet's dayside, where surface temperatures exceed 1500 K due to intense irradiation, producing detectable blackbody-like emission. JWST's Mid-Infrared Instrument (MIRI) enables secondary eclipse observations, where the planet's light is isolated during its passage behind the star, revealing spectral features from silicate vapors or molten rock at wavelengths around 5-12 μm. These observations infer equilibrium temperatures and atmospheric compositions, distinguishing lava worlds from bare-rock or volatile-rich bodies through brightness temperatures derived from flux contrasts.^[38]^[58] Phase curve analysis extends emission spectroscopy by monitoring a planet's thermal emission over its full orbit, mapping longitudinal temperature variations and heat redistribution between dayside and nightside. Infrared phase curves from JWST MIRI capture the eastward shift of hot spots and amplitude differences, indicating low heat transport in tidally locked systems typical of lava planets, with dayside-to-nightside contrasts up to 1000 K. This technique has been applied to probe the global thermal structure, revealing minimal atmospheric circulation on highly irradiated worlds.^[24]^[59] Detecting lava planets presents significant challenges owing to their diminutive size—radii often 1-2 times Earth's—and faint signals overwhelmed by stellar flux, necessitating space-based platforms like TESS and JWST for high-cadence, stable photometry and spectroscopy. Ground-based observations are hampered by telluric absorption and stellar variability, particularly for M-dwarf hosts, limiting radial velocity precision to brighter, quieter systems. Future advancements in telescope sensitivity will be essential to characterize the tenuous rock-vapor atmospheres and surface emissions of these elusive objects.^[60]^[61]

Known Candidates

Several exoplanets have been identified as strong candidates for lava worlds due to their close orbits around host stars, resulting in extreme surface temperatures capable of maintaining molten rock. These planets are typically super-Earths or smaller rocky bodies with orbital periods under one day, leading to intense stellar irradiation. Observations, including thermal emission measurements, support the presence of lava oceans or vaporized rock atmospheres on their daysides. CoRoT-7b, discovered in 2009 by the CoRoT space mission, is one of the earliest known lava planet candidates.^[62] With a radius of approximately 1.58 Earth radii and an orbital period of 0.85 days around its K-type host star, the planet experiences dayside temperatures exceeding 2,000 K, sufficient to melt and vaporize silicate rocks.^[63] Models indicate that its atmosphere may consist of rock vapor, with elements like silicon, iron, and magnesium potentially condensing on the cooler nightside.^[23] Another prominent candidate is 55 Cancri e, a super-Earth detected in 2004 via radial velocity measurements. Orbiting its Sun-like star every 0.7 days with a radius of about 2 Earth radii, the planet has a high density of roughly 6.7 g/cm³, suggesting an iron-rich composition.^[64] Thermal mapping from Spitzer observations reveals dayside temperatures around 2,700 K, consistent with widespread lava oceans and outgassing that could sustain a secondary atmosphere of carbon monoxide and dioxide. Recent JWST observations as of 2024 suggest a possible secondary atmosphere rich in carbon dioxide or carbon monoxide.^[65]^[66]^[67] Kepler-10b, confirmed in 2011 by NASA's Kepler mission, represents a rocky super-Earth with a radius of 1.47 Earth radii and an orbital period of 0.84 days. Its proximity to the G-type host star results in extreme insolation, approximately 3,600 times that received by Earth, driving surface conditions hot enough for potential magma pools despite its density of about 6.5 g/cm³.^[68] Phase curve data from Kepler further indicate a dayside brightness temperature supporting molten surface features.^[69] Analysis of TESS data in 2025 identified TOI-561b as an additional potential lava planet candidate, with models suggesting magma surfaces driven by its ultra-short orbit. TOI-561b, a low-density super-Earth orbiting a G-type star every 0.4 days, shows evidence of a thick volatile atmosphere via JWST observations, likely replenished by evaporation from a lava-covered dayside reaching over 2,000 K.^[70] LHS 3844b, a 1.3 Earth-radii rocky world with a 0.5-day orbit around an M-dwarf first identified as a lava candidate in 2019, exhibits a dark, lava-dominated surface inferred from Spitzer phase curves, with no substantial atmosphere to redistribute heat.^[71]^[72] Confirmation of lava planet status often relies on secondary eclipse depths measured in infrared, which reveal dayside emission temperatures indicative of molten rock (typically above 1,500–2,000 K). These depths, observed via telescopes like Spitzer and JWST, exceed expectations for bare rock surfaces and suggest thermal emission from lava oceans or vapor atmospheres.^[61]^[73]

Scientific Implications

Astrobiological Potential

Lava planets present formidable challenges to habitability due to their extreme surface temperatures, often exceeding 2000 K on the dayside, which would sterilize any potential biosphere through thermal destruction of organic molecules and proteins. High levels of stellar radiation and the absence of stable liquid water further inhibit the development of biochemistry, as water is either vaporized or dissociated in the intense heat, preventing the formation of solvent-based life as known on Earth. These conditions render the surface uninhabitable, with atmospheres dominated by rock vapor and lacking protective layers against cosmic rays. Despite these barriers, possible niches for life may exist in subsurface environments, such as potential liquid layers beneath the nightside crust or within mantle cracks hosting hydrothermal systems driven by tidal heating and residual magma ocean activity. On tidally locked lava planets, the nightside can sustain cooler temperatures around 1500 K, potentially allowing for isolated subsurface reservoirs of volatiles that could support extremophilic organisms analogous to deep-sea vent communities. Hydrothermal vents in such cracks might provide chemical energy gradients for prebiotic chemistry, shielded from surface extremes. Nutrient availability is mixed: silicates, metals, and other rock-derived elements are abundant due to continuous mantle convection and outgassing, but volatiles like water and carbon may be scarce after initial atmospheric escape, though models suggest significant retention in the mantle—up to 130 times Earth's ocean water on super-Earth-sized lava worlds.^[74]^[75]^[76] Analogues to early Earth during the Hadean eon, when a global magma ocean persisted for millions of years post-Moon-forming impact, illustrate transient habitability potential on lava worlds. Earth's magma ocean phase featured extreme heat and toxic atmospheres but transitioned to habitable conditions as it cooled, enabling liquid water oceans and the onset of life around 4.2–3.8 billion years ago. This suggests lava planets could experience brief windows of biospheric viability during cooling episodes before solidifying. Recent 2025 models incorporating tidal-greenhouse feedbacks indicate that Hadean-like magma oceans on exoplanets can sustain habitable epochs lasting 2–320 million years, with oxidizing atmospheres prolonging melt retention and fostering temporary subsurface niches for early life during late-stage solidification.^[77] These insights highlight how evolutionary cooling could briefly enable biospheres on otherwise hostile worlds.^[78]

Research Advances

Recent theoretical models developed by an international team led by researchers at York University have advanced the understanding of lava planet interiors and atmospheres. Published in Nature Astronomy in July 2025, these models simulate the thermal and chemical evolution of lava planets over billions of years, predicting two primary end-member states: fully molten interiors that lead to constant replenishment of a thin, gravitationally unstable crust on the nightside, and mostly solid interiors resulting in a fully solidified mantle with a cold surface. The models also forecast asymmetric atmospheres, where fully molten planets exhibit compositions reflecting the bulk silicate makeup of the planet, including volatiles like sodium, potassium, and iron oxide, while shallower magma oceans deplete these elements.^[53] Observations from the James Webb Space Telescope (JWST) have begun to test these predictions through spectroscopy of candidate lava planets, such as the super-Earth 55 Cancri e. In 2025 analyses using JWST's NIRCam and MIRI instruments, researchers detected absorption features consistent with carbon monoxide (CO) or carbon dioxide (CO₂), indicating a thick, volatile-rich atmosphere likely sustained by outgassing from a molten surface. These findings, detailed in a Proceedings of the National Academy of Sciences study, highlight JWST's capability to probe vapor emissions and thermal structures, with upcoming observations expected to refine interior state inferences for similar worlds.^[79]^[80] Hydrodynamic simulations have further illuminated atmospheric dynamics on lava planets, focusing on escape processes and magma interactions. A 2024 Astronomy & Astrophysics study employed multispecies hydrodynamic models to demonstrate that extensive hydrogen outgassing from small lava planets promotes rapid H₂ escape, while oxidized atmospheres with high molecular weights retain volatiles more effectively, influencing long-term atmospheric retention. Complementing this, radiative-convective models from a December 2024 arXiv preprint reveal conditions for convective shutdown in overlying atmospheres, where intense stellar irradiation suppresses convection above magma oceans, leading to stable thermal profiles that affect heat transport and observability. Additionally, 1D coupled interior-atmosphere simulations in a 2024 Journal of Geophysical Research: Planets paper track magma ocean evolution across redox states, showing how convection drives differentiation and volatile cycling in super-Earth-sized worlds.^[20]^[81]^[82] Despite these advances, significant gaps persist in lava planet research, particularly for super-Earth-sized examples, where limited observational data hinders comprehensive characterization. Current knowledge relies heavily on a handful of candidates, underscoring the need for multi-wavelength surveys to capture diverse interior states and atmospheric compositions beyond visible and near-infrared spectra.^[8]^[1] Lava planet studies also provide interdisciplinary insights into early Solar System evolution, mirroring the magma ocean phase of proto-Earth. The York models illustrate cooling pathways from fully molten to differentiated states, akin to Earth's Hadean eon, where similar convective processes facilitated core-mantle separation and volatile outgassing that shaped the planet's initial atmosphere.^[53]^[8]

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[PDF] arXiv:2306.10100v1 [astro-ph.EP] 16 Jun 2023
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[2405.09284] Volatile atmospheres of lava worlds - arXiv
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Hydrogenated atmospheres of lava planets
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[2412.11987] Convective shutdown in the atmospheres of lava worlds
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