Hostname: page-component-797576ffbb-42xl8 Total loading time: 0 Render date: 2023-12-09T09:47:37.215Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "useRatesEcommerce": true } hasContentIssue false

Presence of water on exomoons orbiting free-floating planets: a case study

Published online by Cambridge University Press:  08 June 2021

Patricio Javier Ávila*
Departamento de Astronomía, Facultad Ciencias Físicas y Matemáticas, Universidad de Concepción, Av. Esteban Iturra s/n Barrio Universitario, Casilla 160, Concepción, Chile
Tommaso Grassi
Ludwig Maximilian University of Munich, Scheinerstr. 1, D-81673 Munich, Germany
Stefano Bovino
Departamento de Astronomía, Facultad Ciencias Físicas y Matemáticas, Universidad de Concepción, Av. Esteban Iturra s/n Barrio Universitario, Casilla 160, Concepción, Chile
Andrea Chiavassa
Universitè Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Bd de l'Observatoire, CS 34229, F-06304 Nice Cedex 4, France European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München, Germany
Barbara Ercolano
Ludwig Maximilian University of Munich, Scheinerstr. 1, D-81673 Munich, Germany
Sebastian Oscar Danielache
Department of Material and Life Sciences, Faculty of Science and Technology, Sophia University, 8 Chiyoda, Tokyo 102-8554, Japan Earth and Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
Eugenio Simoncini
Earth and Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
Author for correspondence: Patricio Javier Ávila, E-mail:


A free-floating planet (FFP) is a planetary-mass object that orbits around a non-stellar massive object (e.g. a brown dwarf) or around the Galactic Centre. The presence of exomoons orbiting FFPs has been theoretically predicted by several models. Under specific conditions, these moons are able to retain an atmosphere capable of ensuring the long-term thermal stability of liquid water on their surface. We model this environment with a one-dimensional radiative-convective code coupled to a gas-phase chemical network including cosmic rays and ion-neutral reactions. We find that, under specific conditions and assuming stable orbital parameters over time, liquid water can be formed on the surface of the exomoon. The final amount of water for an Earth-mass exomoon is smaller than the amount of water in Earth oceans, but enough to host the potential development of primordial life. The chemical equilibrium time-scale is controlled by cosmic rays, the main ionization driver in our model of the exomoon atmosphere.

Research Article
Copyright © The Author(s), 2021. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Badescu, V (2010) Tables of Rosseland mean opacities for candidate atmospheres of life hosting free-floating planets. Central European Journal of Physics 8, 463479.Google Scholar
Badescu, V (2011 a) Thermodynamic constrains for life based on non-aqueous polar solvents on free-floating planets. Origins of Life and Evolution of the Biosphere 41, 7399.CrossRefGoogle ScholarPubMed
Badescu, V (2011 b) Constraints on the free-floating planets supporting aqueous life. Acta Astronautica 69, 788808.CrossRefGoogle Scholar
Badescu, V (2011 c) Free-floating planets as potential seats for aqueous and non-aqueous life. Icarus 216, 485491.CrossRefGoogle Scholar
Barclay, T, Quintana, EV, Raymond, SN and Penny, MT (2017) The demographics of Rocky free-floating planets and their detectability by WFIRST. Astrophysical Journal 841, 86.CrossRefGoogle Scholar
Barnes, JW and O'Brien, DP (2002) Stability of satellites around close-in extrasolar giant planets. The Astrophysical Journal 575, 10871093.CrossRefGoogle Scholar
Becker, JK, Black, JH, Safarzadeh, M, Schuppan, F (2011) Tracing the sources of cosmic rays with molecular ions. The Astrophysical Journal 739, L43.CrossRefGoogle Scholar
Bennett, DP, Batista, V, Bond, IA, Bennet, CS, Susuki, D, Beaulieu, JP, Udalski, A, Donatowicz, J, Bozza, V, Abe, F, Botzler, CS, Freeman, M, Fukunaga, D, Fukui, A, Itow, Y, Koshimoto, N, Ling, CH, Masuda, K, Matsubara, Y, Muraki, Y, Namba, S, Ohnishi, K, Rattenbury, NJ, Saito To, , Sullivan, DJ, Sumi, T, Sweatman, WL, Tristram, PJ, Tsurumi, N, Wada, K, Yock, PCM, Albrow, MD, Bachelet, E, Brillant, S, Caldwell, JAR, Cassan, A, Cole, AA, Corrales, E, Coutures, C, Dieters, S, Dominis Prester, D, Fouqué, P, Greenhill, J, Horne, J, Koo, JR, Kubas, D, Marquette, JB, Martin, R, Menzies, JW, Sahu, KC, Wambsganss, J, Williams, A, Zub, M, Choi, JY, DePoy, DL, Dong, S, Gaudi, BS, Gould, A, Han, C, Henderson, CB, McGregor, D, Lee, CU, Pogge, RW, Shin, IG, Yee, JC, Szymański, MK, Skowron, J, Poleski, R, Kozłowski, S, Wyrzykowski, Ł, Kubiak, M, Pietrukowicz, P, Pietrzyński, G, Soszyński, I, Ulaczyk, K, Tsapras, Y, Street, RA, Dominik, M, Bramich, DM, Browne, P, Hundertmark, M, Kains, N, Snodgrass, C, Steele, IA, Dekany, I, Gonzalez, OA, Heyrovský, D, Kandori, R, Kerins, E, Lucas, PW, Minniti, D, Nagayama, T, Rejkuba, M, Robin, AC and Saito, R (2014) MOA-2011-BLG-262Lb: a sub-Earth-mass moon orbiting a gas giant primary or a high velocity planetary system in the Galactic Bulge. The Astrophysical Journal 785, 155.CrossRefGoogle Scholar
Caballero, JA (2018) A review on substellar objects beyond the deuterium burning mass limit: planets, brown dwarfs or what? Geosciences 8, 362398.CrossRefGoogle Scholar
Canup, RM and Ward, WR (2006) A common mass scaling for satellite systems of gaseous planets. Nature 441, 834839.CrossRefGoogle ScholarPubMed
Catling, DC and Zahnle, KJ (2009) The planetary air leak. Scientific American 300, 3643.CrossRefGoogle ScholarPubMed
Choukroun, M, Altwegg, K and Kührt, E (2020) Dust-to-gas and refractory-to-ice mass ratios of Comet 67P/Churyumov-Gerasimenko from Rosetta Observations. Space Science Reviews 216, 44.CrossRefGoogle Scholar
Clanton, C and Gaudi, BS (2016) Synthesizing exoplanet demographics: a single population of long-period planetary companions to M dwarfs consistent with microlensing, radial velocity, and direct imaging surveys. Astrophysical Journal 819, 125.CrossRefGoogle Scholar
Clark, RN, Swayze, GA, Carlson, R, Grundy, W and Noll, K (2014) Spectroscopy from space. Reviews in Mineralogy and Geo-chemistry 78, 399446.CrossRefGoogle Scholar
Dalgarno, A (2006) Interstellar chemistry special feature: the galactic cosmic ray ionization rate. Proceedings of the National Academy of Science 103, 1226912273.CrossRefGoogle Scholar
Debes, JH and Sigurdsson, S (2007 a) The survival rate of ejected terrestrial planets with moons. The Astrophysical Journal 668, 167170.CrossRefGoogle Scholar
Dobos, V, Heller, R and Turner, EL (2017) The effect of multiple heat sources on exomoon habitable zones. Astronomy and Astrophysics 601, A91.CrossRefGoogle Scholar
Dye, ST (2012) Geoneutrinos and the radioactive power of the Earth. Reviews of Geophysics 50, 30073026.CrossRefGoogle Scholar
Fogg, MJ (1990) Interstellar planets. Communications in Astrophysics 14, 357378.Google Scholar
Fox, C and Wiegert, P (2021) MNRAS. Exomoon candidates from transit timing variations: eight Kepler systems with TTVs explainable by photometrically unseen exomoons 510, 23782393.Google Scholar
Glein, CR (2015) Noble gases, nitrogen, and methane from the deep interior to the atmosphere of Titan. Icarus 250, 570586.CrossRefGoogle Scholar
Guillot, T (2010) On the radiative equilibrium of irradiated planetary atmospheres. Astronomy and Astrophysics 520, A27.CrossRefGoogle Scholar
Hansen, BMS (2008) On the absorption and redistribution of energy in irradiated planets. The Astrophysical Journal Supplement Series 179, 484508.CrossRefGoogle Scholar
Haqq-Misra, J and Heller, R (2018) Exploring exomoon atmospheres with an idealized general circulation model. Monthly Notices of the RAS 479, 34773489.CrossRefGoogle Scholar
Heller, R (2012) Exomoon habitability constrained by energy flux and orbital stability. Astronomy and Astrophysics 545, L8.CrossRefGoogle Scholar
Heller, R and Barnes, R (2013 a) Exomoon habitability constrained by illumination and tidal heating. Astrobiology 13, 1853.CrossRefGoogle ScholarPubMed
Heller, R and Barnes, R (2013 b) Magnetic shielding of exomoons beyond the circumplanetary habitable edge. ApJL 776, L33.CrossRefGoogle Scholar
Heller, R and Barnes, R (2014) Constraints on the habitability of extrasolar moons. Formation, Detection, and Characterization of Extrasolar Habitable Planets 293, 159164.Google Scholar
Heller, R, Williams, D, Kipping, D, Limbach, M, Turner, E, Greenberg, R, Sasaki, T, Bolmont, E, Grasset, O, Lewis, K, Barnes, R and Zuluaga, J (2014) Formation, habitability, and oetection of extrasolar moons. Astrobiology 14, 142.CrossRefGoogle ScholarPubMed
Heller, R, Rodenbeck, K and Bruno, G (2019) An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625. Astronomy and Astrophysics 624, A95.CrossRefGoogle Scholar
Henderson, CB (2016) Using K2 to find free-floating planets. American Astronomical Society Meeting Abstracts 227, 122.09.Google Scholar
Henning, WG, O'Connell, RJ and Sasselov, DD (2009) Tidally heated terrestrial exoplanets: viscoelastic response models. Astrophysical Journal 707, 10001015.CrossRefGoogle Scholar
Hindmarsh, AC, Brown, PN, Grant, KE, Lee, SL, Serban, R, Shumaker, DE and Woodward, CS (2005) SUNDIALS: suite of nonlinear and differential/algebraic equation solvers. ACM Transactions on Mathematical Software (TOMS) 31, 3.CrossRefGoogle Scholar
Hong, YC, Raymond, SN, Nicholson, PD and Lunine, JI (2018) Innocent bystanders: orbital dynamics of exomoons during planet-planet scattering. Astrophysical Journal 852, 85.CrossRefGoogle Scholar
Hu, R, Seager, S and Bains, W (2012) Photochemistry in terrestrial exoplanet atmospheres. I. photochemistry model and benchmark cases. The Astrophysical Journal 761, 166.CrossRefGoogle Scholar
Jakosky, BM and Farmer, CB (1982) The seasonal and global behavior of water vapor in the Mars atmosphere: complete global results of the Viking Atmospheric Water Detector Experiment. Elsevier Science, pp. 186.CrossRefGoogle Scholar
Jaupart, C, Labrosse, S and Mareschal, JC (2007) Treatise on geophysics. Journal of Geophysical Research 87, B4.Google Scholar
Jin, Z and Bose, M (2019) New clues to ancient water on Itokawa. Science Advances 5, 5.CrossRefGoogle ScholarPubMed
Kasting, JF (1982) Stability of ammonia in the primitive terrestrial atmosphere. JGR Oceans 87, 30913098.CrossRefGoogle Scholar
Kasting, JF, Whitmire, DP and Reynolds, RT (1993) Habitable zones around main sequence stars. Icarus 101, 108128.CrossRefGoogle ScholarPubMed
Kipping, D, Bakos, G, Buchhave, L, Nesvorný, D and Schmitt, A (2012) The hunt for exomoons with kepler (HEK): I. description of a New Observational Project. The Astrophysical Journal 750, 115134.CrossRefGoogle Scholar
Kreidberg, L, Luger, R and Bedell, M (2019) No evidence for lunar transit in new analysis of hubble space telescope observations of the Kepler-1625 system. Astrophysical Journal Letters 877, L15.CrossRefGoogle Scholar
Lammer, H, Bredehöft, JH and Coustenis, A (2009) What makes a planet habitable?. The Astronomy and Astrophysics Review 17, 181249.CrossRefGoogle Scholar
Lammer, H, Schiefer, SC, Juvan, I, Odert, P, Erkaev, NV, Weber, C, Kislyakova, KG, Güdel, M, Kirchengast, G and Hanslmeier, A (2014) Origin and stability of exomoon atmospheres: implications for habitability. Origins of Life and Evolution of the Biosphere 44, 239260.CrossRefGoogle ScholarPubMed
Lammer, H, Zerkle, AL, Gebauer, S, Tosi, N, Noack, L, Scherf, M, Pilat-Lohinger, E, Güdel, M, Grenfell, JL, Godolt, M and Nikolaou, A (2018) Origin and evolution of the atmospheres of early Venus, Earth and Mars. Astronomy and Astrophysics Reviews 26, 2.CrossRefGoogle Scholar
Laughlin, G and Adams, FC (2000) The frozen earth: binary scattering events and the fate of the solar system. Icarus 145, 614627.CrossRefGoogle Scholar
Lebrun, T, Massol, H, ChassefièRe, E, Davaille, A, Marcq, E, Sarda, P, Leblanc, F and Brandeis, G (2013) Thermal evolution of an early magma ocean in interaction with the atmosphere. Journal of Geophysical Research (Planets) 118, 11551176.CrossRefGoogle Scholar
Lehmer, OR, Catling, DC and Zahnle, KJ (2017) The longevity of water ice on Ganymedes and Europas around migrated giant planets. The Astrophysical Journal 839, 3241.CrossRefGoogle Scholar
Lissauer, JJ (1987) Timescales for planetary accretion and the structure of the protoplanetary disk. Icarus 69, 249265.CrossRefGoogle Scholar
Liu, MC, Magnier, EA, Deacon, NR, Allers, KN, Dupuy, TJ, Kotson, MC, Aller, KM, Burgett, WS, Chambers, KC, Draper, PW, Hodapp, KW, Jedicke, R, Kaiser, N, Kudritzki, RP, Metcalfe, N, Morgan, JS, Price, PA, Tonry, JL and Wainscoat, RJ (2013) The extremely Red, Young L Dwarf PSO J318.5338-22.8603: a free-floating Planetary-mass analog to directly imaged young gas-giant planets. The Astrophysical Journal Letters 777, 2027.CrossRefGoogle Scholar
Liu, MC, Dupuy, TJ and Allers, KN (2016) The Hawaii Infrared Parallax Program. II. young ultracool field dwarfs. The Astrophysical Journal 833, 96161.CrossRefGoogle Scholar
Luhman, KL (2014) Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun. The Astrophysical Journal Letters 786, L18.CrossRefGoogle Scholar
Mandt, KE, Mousis, O, Lunine, J and Gautier, D (2014) Protosolar ammonia as the unique source of Titan's nitrogen. The Astrophysical Journal Letters 788, L24.CrossRefGoogle ScholarPubMed
Marley, MS and Robinson, TD (2015) On the cool side: modeling the atmospheres of brown dwarfs and giant planets. Annual Review of Astronomy and Astrophysics 53, 279323.CrossRefGoogle Scholar
Massol, H, Hamano, K, Tian, F, Ikoma, M, Abe, Y, Chassefière, E, Davaille, A, Genda, H, Güdel, M, Hori, Y, Leblanc, F, Marcq, E, Sarda, P, Shematovich, VI, Stökl, A and Lammer, H (2016) Formation and evolution of protoatmospheres. Space Science Reviews 205, 153211.CrossRefGoogle Scholar
Molina-Cuberos, GJ, Lichtenegger, H, Schwingenschuh, K, López-Moreno, JJ and Rodrigo, R (2002) Ion-neutral chemistry model of the lower ionosphere of Mars. J. Geophys. Res., 107, E5.Google Scholar
Mróz, P, Ryu, YH, Skowron, J, Udalski, A, Gould, A, Szymanski, MK, Soszynsk, I, Poleski, R, Pietrukowicz, P, Kozlowski, S, Pawlak, M, Ulaczyk, K, Albrow, MD, Chung, SJ, Jung, YK, Han, C, Hwang, KH, Shin, IG, Yee, JC, Zhu, W, Cha, SM, Kim, DJ, Kim, HW, Kim, SL, Lee, CU, Lee, DJ, Lee, Y, Park, BG and Pogge, RW (2018) A Neptune-mass Free-floating Planet candidate discovered by microlensing surveys. The Astronomical Journal 155, 121127.CrossRefGoogle Scholar
Mróz, P, Poleski, R, Han, C, Udalski, A, Gould, A, Szymanski, MK, Soszynski, I, Pietrukowicz, P, Kozlowski, S, Skowron, J, Ulaczyk, K, Gromadzki, M, Rybicki, K, Iwanek, P, Wrona, M, Albrow, MD, Chung, S, Hwang, K, Ryu, Y, Jung, YK, Shin, I, Shvartzvald, Y, Yee, JC, Zang, W, Cha, S, Kim, D, Kim, H, Kim, S, Lee, C, Lee, D, Lee, Y, Park, B and Pogge, RW (2020) A free-floating or wide-orbit planet in the microlensing event OGLE-2019-BLG-0551 arXiv e-prints, arXiv:200301126.CrossRefGoogle Scholar
Murray, CD and Dermott, SF (2000) Solar System Dynamics. Cambridge University Press, pp. 130186.CrossRefGoogle Scholar
Nimmo, F and Pappalardo, RT (2016) Ocean worlds in the outer solar system. Journal of Geophysical Research: Planets 121, 13781399.Google Scholar
Nordheim, TA, Jasinski, JM and Hand, KP (2019) Galactic cosmic-ray bombardment of Europa's surface. ApJL 881, L29.CrossRefGoogle Scholar
Öpik, EJ (1964) Stellar planets and little dark stars as possible seats of life. Irish Astronomical Journal 6, 290296.Google Scholar
Parmentier, V and Guillot, T (2014) A non-grey analytical model for irradiated atmospheres. I. Derivation. Astronomy and Astrophysics 562, A133.CrossRefGoogle Scholar
Pollack, JB and Yung, YL (1980) Origin and evolution of planetary atmospheres. Annual Review of Earth and Planetary Sciences 8, 425.CrossRefGoogle Scholar
Rabago, I and Steffen, JH (2019) Survivability of moon systems around ejected gas giants. Monthly Notices of the RAS 489, 23232329.CrossRefGoogle Scholar
Reynolds, RT and Cassen, PM (1978) SInternal structure of large, icy satellites. EOS Transactions 59, 1123.Google Scholar
Rimmer, PB and Helling, C (2013) Ionization in atmospheres of brown dwarfs and extrasolar planets. IV. The effect of cosmic rays. Astrophysical Journal 774, 108124.CrossRefGoogle Scholar
Rimmer, PB and Helling, C (2016) A chemical kinetics network for lightning and life in planetary atmospheres. The Astrophysical Journal Supplement Series 224, 942.CrossRefGoogle Scholar
Robinson, TD and Catling, DC (2012) An analytic radiative-convective model for planetary atmospheres. The Astrophysical Journal 757, 104117.CrossRefGoogle Scholar
Rodenbeck, K, Heller, R, Hippke, M and Gizon, L (2018) Revisiting the exomoon candidate signal around Kepler-1625 b. Astronomy and Astrophysics 617, A49.CrossRefGoogle Scholar
Sagan, C (1969) Gray and nongray planetary atmospheres structure, convective instability, and greenhouse effect. Icarus 10, 290300.CrossRefGoogle Scholar
Scharf, CA (2006) Instruments, Methods, and Missions for Astrobiology IX. San Diego: Society of Photo-optical Instrumentation Engineers, pp. 171185.Google Scholar
Shapley, H (1958) Of Stars and Men. The Human Response to an Expanding Universe. London: Elek Books, p. 56.Google Scholar
Shapley, H (1962) The scholar cornered: crusted stars and self-warming planets. The American Scholar 31, 512515.Google Scholar
Stevenson, DJ (1999) Life-sustaining planets in interstellar space?. Nature 400, 32.CrossRefGoogle ScholarPubMed
Sumi, T, Kamiya, K, Bennett, DP, Bond, IA, Abe, F, Botzler, CS, Fukui, A, Furusawa, K, Hearnshaw, JB, Itow, Y, Kilmartin, PM, Korpela, A, Lin, W, Ling, CH, Masuda, K, Matsubara, Y, Miyake, N, Motomura, M, Muraki, Y, Nagaya, M, Nakamura, S, Ohnishi, K, Okumura, T, Perrot, YC, Rattenbury, N, Saito, To, Sako, T, Sullivan, DJ, Sweatman, WL, Tristram, PJ, Yock, PCM, Szymanski, MK, Kubiak, M, Pietrzynski, G, Poleski, R, Soszynski, I, Wyrzykowski, L and Ulaczyk, K (2011) Unbound or distant planetary mass population detected by gravitational microlensing. Nature 473, 349352.Google Scholar
Svedhem, H, Titov, D, Taylor, F and Witasse, O (2007) Venus as a more Earth-like planet. Nature 450, 629632.CrossRefGoogle ScholarPubMed
Teachey, A and Kipping, DM (2018) Evidence for a large exomoon orbiting Kepler-1625b. Science Advances 4, eaav1784.CrossRefGoogle ScholarPubMed
Teachey, A, Kipping, DM and Schmitt, AR (2018) HEK. VI. On the dearth of Galilean analogs in Kepler, and the exomoon candidate Kepler-1625b I. The Astronomical Journal 155, 36.CrossRefGoogle Scholar
Trenberth, KE and Smith, L (2018) The mass of the atmosphere: a constraint on global analyses. Journal of Climate 18, e864e875.CrossRefGoogle Scholar
Tsai, SM, Lyons, JR, Grosheintz, L, Rimmer, PB, Kitzmann, D and Heng, K (2017) VULCAN: an open-source, validated chemical kinetics python code for exoplanetary atmospheres. The Astrophysical Journal Supplement Series 228, 2046.CrossRefGoogle Scholar
Wakelam, V, Loison, JC, Herbst, E, Pavone, B, Bergeat, A, Béroff, K, Chabot, M, Faure, A, Galli, D, Geppert, WD, Gerlich, D, Gratier, P, Harada, N, Hickson, KM, Honvault, P, Klippenstein, SJ, Le Picard, SD, Nyman, G, Ruaud, M, Schlemmer, S, Sims, IR, Talbi, D, Tennyson, J and Wester, R (2015) The 2014 KIDA network for interstellar chemistry. The Astrophysical Journal Supplement Series 217, 20.CrossRefGoogle Scholar
Wallace, J and Hobbs, P (2006) Atmospheric Science: An Introductory Survey. Londres: Academic press, pp. 86.Google Scholar
Way, MJ and Del Genio, AD (2020) Venusian habitable climate scenarios: modeling venus through time and applications to slowly rotating venus-like exoplanets. Journal of Geophysical Research (Planets) 125(5), e2019JE006276.Google Scholar
Weast, RC (1979) CRC Handbook of Chemistry and Physics. A Ready-Reference Book of Chemical and Physical Data. Ohio: Chemical Rubber Comp. Press..Google Scholar
Weaver, CP and Ramanathan, V (1995) Deductions from a simple climate model: factors governing surface temperature and atmospheric thermal structure. Journal of Geophysical Research 100, 1158511592.CrossRefGoogle Scholar
Williams, DM (2013) Capture of terrestrial-sized moons by gas giant planets. Astrobiology 13, 315323.CrossRefGoogle ScholarPubMed
Yoder, CF and Peale, SJ (1981) The tides of Io. Icarus 47, 135.CrossRefGoogle Scholar
Zapatero Osorio, MR, Béjar, VJS, Martín, EL, Rebolo, R, Barrado y Navascués, D, Bailer-Jones, CAL and Mundt, R (2000) Discovery of young isolated planetary mass objects in the σ orionis star cluster. Science 290, 103107.CrossRefGoogle ScholarPubMed
Zhong, W and Haigh, JD (2013) The greenhouse effect and carbon dioxide. Weather 68, 100105.CrossRefGoogle Scholar