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Fulton, B. J. et al. The California-Kepler survey. III. A spot within the radius distribution of small planets. Astron. J. 154, 109 (2017).
Bean, J. L., Raymond, S. N. & Owen, J. E. The nature and origins of sub-Neptune measurement planets. J. Geophys. Res. Planets 126, e2020JE006639 (2021).
Bitsch, B. et al. Dry or water world? How the water contents of internal sub-Neptunes constrain large planet formation and the placement of the water ice line. Astron. Astrophys. 649, L5 (2021).
Misener, W., Schlichting, H. E. & Young, E. D. Atmospheres as home windows into sub-Neptune interiors: coupled chemistry and construction of hydrogen–silane–water envelopes. Mon. Not. R. Astron. Soc. 524, 981–992 (2023).
Schlichting, H. E. & Young, E. D. Chemical equilibrium between cores, mantles, and atmospheres of super-Earths and sub-Neptunes and implications for his or her compositions, interiors, and evolution. Planet. Sci. J. 3, 127 (2022).
Morbidelli, A. et al. Source areas and timescales for the supply of water to the Earth. Meteorit. Planet. Sci. 35, 1309–1320 (2000).
Ikoma, M. & Genda, H. Constraints on the mass of a liveable planet with water of nebular origin. Astrophys. J. 648, 696 (2006).
Hallis, L. J. et al. Evidence for primordial water in Earth’s deep mantle. Science 350, 795–797 (2015).
Young, E. D., Shahar, A. & Schlichting, H. E. Earth formed by primordial H2 atmospheres. Nature 616, 306–311 (2023).
Howard, A. W. et al. Planet incidence inside 0.25 AU of solar-type stars from Kepler. Astrophys. J. Suppl. Ser. 201, 15 (2012).
Owen, J. E. & Wu, Y. Kepler planets: a story of evaporation. Astrophys. J. 775, 105 (2013).
Ginzburg, S., Schlichting, H. E. & Sari, R. Core-powered mass-loss and the radius distribution of small exoplanets. Mon. Not. R. Astron. Soc. 476, 759–765 (2018).
Zeng, L. et al. Growth mannequin interpretation of planet measurement distribution. Proc. Natl Acad. Sci. USA 116, 9723–9728 (2019).
Venturini, J. & Helled, R. Jupiter’s heavy-element enrichment anticipated from formation fashions. Astron. Astrophys. 634, A31 (2020).
Luque, R. & Pallé, E. Density, not radius, separates rocky and water-rich small planets orbiting M dwarf stars. Science 377, 1211–1214 (2022).
Piaulet, C. et al. Evidence for the volatile-rich composition of a 1.5-Earth-radius planet. Nat. Astron. 7, 206–222 (2022).
Piaulet-Ghorayeb, C. et al. JWST/NIRISS reveals the water-rich “Steam World” environment of GJ 9827 d. Astrophys. J. Lett. 974, L10 (2024).
Hirschmann, M. M., Withers, A. C., Ardia, P. & Foley, N. T. Solubility of molecular hydrogen in silicate melts and penalties for unstable evolution of terrestrial planets. Earth Planet. Sci. Lett. 345, 38–48 (2012).
Kite, E. S., Fegley, B. Jr, Schaefer, L. & Ford, E. B. Superabundance of exoplanet sub-neptunes defined by fugacity disaster. Astrophys. J. Lett. 887, L33 (2019).
Sabat, Okay. C., Rajput, P., Paramguru, R. Okay., Bhoi, B. & Mishra, B. Okay. Reduction of oxide minerals by hydrogen plasma: an summary. Plasma Chem. Plasma Process. 34, 1–23 (2014).
Kimura, T. & Ikoma, M. Predicted range in water content material of terrestrial exoplanets orbiting M dwarfs. Nat. Astron. 6, 1296–1307 (2022).
Krissansen-Totton, J., Wogan, N., Thompson, M. & Fortney, J. J. The erosion of enormous major atmospheres usually leaves behind substantial secondary atmospheres on temperate rocky planets. Nat. Commun. 15, 8374 (2024).
Horn, H. W., Prakapenka, V., Chariton, S., Speziale, S. & Shim, S.-H. Reaction between hydrogen and ferrous/ferric oxides at excessive pressures and excessive temperatures—implications for sub-neptunes and super-earths. Planet. Sci. J. 4, 30 (2023).
Kim, T. et al. Stability of hydrides in sub-Neptune exoplanets with thick hydrogen-rich atmospheres. Proc. Natl Acad. Sci. USA 120, e2309786120 (2023).
Shinozaki, A. et al. Influence of H2 fluid on the soundness and dissolution of Mg2SiO4 forsterite beneath excessive strain and excessive temperature. Am. Mineral. 98, 1604–1609 (2013).
Shinozaki, A. et al. Formation of SiH4 and H2O by the dissolution of quartz in H2 fluid beneath excessive strain and temperature. Am. Mineral. 99, 1265–1269 (2014).
Stökl, A., Dorfi, E. A., Johnstone, C. P. & Lammer, H. Dynamical accretion of primordial atmospheres round planets with lots between 0.1 and 5 M⊕ within the liveable zone. Astrophys. J. 825, 86 (2016).
Vazan, A., Ormel, C. W., Noack, L. & Dominik, C. Contribution of the core to the thermal evolution of sub-Neptunes. Astrophys. J. 869, 163 (2018).
Goncharov, A. F. et al. X-ray diffraction within the pulsed laser heated diamond anvil cell. Rev. Sci. Instrum. 81, 113902 (2010).
Shen, G. & Lazor, P. Measurement of melting temperatures of some minerals beneath decrease mantle pressures. J. Geophys. Res. Solid Earth 100, 17699–17713 (1995).
Gupta, A., Stixrude, L. & Schlichting, H. E. The miscibility of hydrogen and water in planetary atmospheres and interiors. Astrophys. J. Lett. 982, L35 (2025).
Kim, T. et al. Atomic-scale mixing between MgO and H2O within the deep interiors of water-rich planets. Nat. Astron. 5, 815–821 (2021).
Hirschmann, M. M., Aubaud, C. & Withers, A. C. Storage capability of H2O in nominally anhydrous minerals within the higher mantle. Earth Planet. Sci. Lett. 236, 167–181 (2005).
Karki, B. B., Ghosh, D. B. & Bajgain, S. Okay. in Magmas Under Pressure 419–453 (Elsevier, 2018).
Putirka, Okay. D. & Xu, S. Polluted white dwarfs reveal unique mantle rock varieties on exoplanets in our photo voltaic neighborhood. Nat. Commun. 12, 6168 (2021).
Aguichine, A., Mousis, O., Deleuil, M. & Marcq, E. Mass–radius relationships for irradiated ocean planets. Astrophys. J. 914, 84 (2021).
Vazan, A., Sari, R. & Kessel, R. A brand new perspective on the interiors of ice-rich planets: ice-rock combination as a substitute of ice on prime of rock. Astrophys. J. 926, 150 (2022).
Luo, H., Dorn, C. & Deng, J. The inside because the dominant water reservoir in super-Earths and sub-Neptunes. Nat. Astron. 8, 1399–1407 (2024).
Venturini, J., Guilera, O. M., Haldemann, J., Ronco, M. P. & Mordasini, C. The nature of the radius valley: hints from formation and evolution fashions. Astron. Astrophys. 643, L1 (2020).
Burn, R. et al. A radius valley between migrated steam worlds and evaporated rocky cores. Nat. Astron. 8, 463–471 (2024).
Madhusudhan, N., Piette, A. A. A. & Constantinou, S. Habitability and biosignatures of hycean worlds. Astrophys. J. 918, 1 (2021).
Cherubim, C. et al. TOI-1695 b: a water world orbiting an early-M dwarf within the planet radius valley. Astron. J. 165, 167 (2023).
Osborne, H. L. M. et al. TOI-544 b: a possible water-world contained in the radius valley in a two-planet system. Mon. Not. R. Astron. Soc. 527, 11138–11157 (2023).
Izidoro, A. et al. The exoplanet radius valley from gas-driven planet migration and breaking of resonant chains. Astrophys. J. Lett. 939, L19 (2022).
Piermarini, G. J., Block, S., Barnett, J. D. & Forman, R. A. Calibration of the strain dependence of the R1 ruby fluorescence line to 195 kbar. J. Appl. Phys. 46, 2774–2780 (1975).
Prakapenka, V. et al. Advanced flat prime laser heating system for prime strain analysis at GSECARS: software to the melting conduct of germanium. High Press. Res. 28, 225–235 (2008).
Deemyad, S. et al. Pulsed laser heating and temperature dedication in a diamond anvil cell. Rev. Sci. Instrum. 76, 125104 (2005).
Fu, S., Chariton, S., Prakapenka, V. B., Chizmeshya, A. & Shim, S.-H. Stable hexagonal ternary alloy part in Fe-Si-H at 28.6–42.2 GPa and 3000 Okay. Phys. Rev. B 105, 104111 (2022).
Fu, S., Chariton, S., Prakapenka, V. B. & Shim, S.-H. Core origin of seismic velocity anomalies at Earth’s core–mantle boundary. Nature 615, 646–651 (2023).
Kulka, B. L., Dolinschi, J. D., Leinenweber, Okay. D., Prakapenka, V. B. & Shim, S.-H. The bridgmanite–akimotoite–majorite triple level decided in massive quantity press and laser-heated diamond anvil cell. Minerals 10, 67 (2020).
Prescher, C. & Prakapenka, V. B. DIOPTAS: a program for discount of two-dimensional X-ray diffraction information and information exploration. High Press. Res. 35, 223–230 (2015).
Shim, S.-H. PeakPo: a python software program for x-ray diffraction evaluation at excessive strain and excessive temperature. Zenodo (2019).
Ye, Y., Prakapenka, V., Meng, Y. & Shim, S.-H. Intercomparison of the gold, platinum, and MgO strain scales as much as 140 GPa and 2500 Okay. J. Geophys. Res. Solid Earth 122, 3450–3464 (2017).
Dewaele, A., Fiquet, G. & Gillet, P. Temperature and strain distribution within the laser-heated diamond–anvil cell. Rev. Sci. Instrum. 69, 2421–2426 (1998).
Holtgrewe, N., Greenberg, E., Prescher, C., Prakapenka, V. B. & Goncharov, A. F. Advanced built-in optical spectroscopy system for diamond anvil cell research at GSECARS. High Press. Res. 39, 457–470 (2019).
Vazan, A., Helled, R., Kovetz, A. & Podolak, M. Convection and mixing in large planet evolution. Astrophys. J. 803, 32 (2015).
Saumon, D., Chabrier, G. & van Horn, H. M. An equation of state for low-mass stars and large planets. Astrophys. J. Suppl. Ser. 99, 713 (1995).
Vazan, A., Kovetz, A., Podolak, M. & Helled, R. The impact of composition on the evolution of large and intermediate-mass planets. Mon. Not. R. Astron. Soc. 434, 3283–3292 (2013).
Freedman, R. S. et al. Gaseous imply opacities for big planet and ultracool dwarf atmospheres over a variety of metallicities and temperatures. Astrophys. J. Suppl. Ser. 214, 25 (2014).
Shim, S.-H. Experimental information for hydrogen-silicate response [Data set]. Zenodo (2025).
Shim, S.-H. Jupyter notebooks for Supplementary Codes (0.0.1). Zenodo (2025).
Sakamaki, Okay. et al. Melting part relation of FeHx as much as 20 GPa: implication for the temperature of the Earth’s core. Phys. Earth Planet. Interiors 174, 192–201 (2009).
Mosenfelder, J. L., Asimow, P. D. & Ahrens, T. J. Thermodynamic properties of Mg2SiO4 liquid at ultra-high pressures from shock measurements to 200 GPa on forsterite and wadsleyite. J. Geophys. Res. Solid Earth 112, B06208 (2007).
Ohtani, E. Melting relation of Fe2SiO4 as much as about 200 kbar. J. Phys. Earth 27, 189–208 (1979).
Andrault, D. et al. Melting conduct of SiO2 as much as 120 GPa. Phys. Chem. Miner. 47, 10 (2020).
Zha, C., Liu, H., Tse, J. S. & Hemley, R. J. Melting and excessive P–T transitions of hydrogen as much as 300 GPa. Phys. Rev. Lett. 119, 075302 (2017).
Narygina, O. et al. X-ray diffraction and Mössbauer spectroscopy research of fcc iron hydride FeH at excessive pressures and implications for the composition of the Earth’s core. Earth Planet. Sci. Lett. 307, 409–414 (2011).
Thompson, E. et al. High-pressure geophysical properties of fcc part FeHX. Geochem. Geophys. Geosyst. 19, 305–314 (2018).
Kato, C. et al. Stability of fcc part FeH to 137 GPa. Am. Mineral. 105, 917–921 (2020).
Tagawa, S., Gomi, H., Hirose, Okay. & Ohishi, Y. High-temperature equation of state of FeH: implications for hydrogen in Earth’s internal core. Geophys. Res. Lett. 49, e2021GL096260 (2022).
Ikuta, D. et al. Interstitial hydrogen atoms in face-centered cubic iron within the Earth’s core. Sci. Rep. 9, 7108 (2019).
Shibazaki, Y. et al. High-pressure and high-temperature part diagram for Fe0.9Ni0.1–H alloy. Phys. Earth Planet. Inter. 228, 192–201 (2014).
Ohta, Okay., Suehiro, S., Hirose, Okay. & Ohishi, Y. Electrical resistivity of fcc part iron hydrides at excessive pressures and temperatures. Comptes Rendus Geosci. 351, 147–153 (2019).
Dorogokupets, P. I., Dymshits, A. M., Litasov, Okay. D. & Sokolova, T. S. Thermodynamics and equations of state of iron to 350 GPa and 6000 Okay. Sci. Rep. 7, 41863 (2017).
Piet, H. et al. Superstoichiometric alloying of H and close-packed Fe-Ni metallic beneath excessive pressures: implications for hydrogen storage in planetary core. Geophys. Res. Lett. 50, e2022GL101155 (2023).
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