12 results on '"Nordheim, Tom"'
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2. Detection of HCN and diverse redox chemistry in the plume of Enceladus
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Peter, Jonah S., Nordheim, Tom A., and Hand, Kevin P.
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Earth and Planetary Astrophysics (astro-ph.EP) ,FOS: Physical sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The Cassini spacecraft discovered that Saturn's moon Enceladus possesses a series of jets erupting from its South Polar Terrain. Previous studies of in situ data collected by Cassini's Ion and Neutral Mass Spectrometer (INMS) have identified H$_2$O, CO$_2$, CH$_4$, H$_2$, and NH$_3$ within the plume of ejected material. Identification of minor species in the plume remains an ongoing challenge, owing to the large number of possible combinations that can be used to fit the INMS data. Here, we present the discovery of several new compounds of strong importance to the habitability of Enceladus, including HCN, CH$_2$O, C$_2$H$_2$, and C$_3$H$_6$. Our analyses of the low velocity INMS data coupled with our detailed statistical framework enable discriminating between previously ambiguous species in the plume by alleviating the effects of high-dimensional model fitting. Together with plausible mineralogical catalysts and redox gradients derived from surface radiolysis, these compounds could potentially support extant microbial communities or drive complex organic synthesis leading to the origin of life., 20 pages, 8 figures
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- 2023
3. A CO2 cycle on Ariel? Radiolytic production and migration to low latitude cold traps
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Cartwright, Richard J., Nordheim, Tom A., DeColibus, David, Grundy, William M., Holler, Bryan J., Beddingfield, Chloe B., Sori, Michael M., Lucas, Michael P., Elder, Catherine M., Regoli, Leonardo H., Cruikshank, Dale P., Emery, Joshua P., Leonard, Erin J., and Cochrane, Corey J.
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Earth and Planetary Astrophysics (astro-ph.EP) ,FOS: Physical sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
CO2 ice is present on the trailing hemisphere of Ariel but is mostly absent from its leading hemisphere. The leading/trailing hemispherical asymmetry in the distribution of CO2 ice is consistent with radiolytic production of CO2, formed by charged particle bombardment of H2O ice and carbonaceous material in Ariel's regolith. This longitudinal distribution of CO2 on Ariel was previously characterized using 13 near-infrared reflectance spectra collected at 'low' sub-observer latitudes between 30S to 30N. Here, we investigated the distribution of CO2 ice on Ariel using 18 new spectra: two collected over low sub-observer latitudes, five collected at 'mid' sub-observer latitudes (31 - 44N), and eleven collected over 'high' sub-observer latitudes (45 - 51N). Analysis of these data indicates that CO2 ice is primarily concentrated on Ariel's trailing hemisphere. However, CO2 ice band strengths are diminished in the spectra collected over mid and high sub-observer latitudes. This sub-observer latitudinal trend may result from radiolytic production of CO2 molecules at high latitudes and subsequent migration of this constituent to low latitude cold traps. We detected a subtle feature near 2.13 microns in two spectra collected over high sub-observer latitudes, which might result from a 'forbidden' transition mode of CO2 ice that is substantially stronger in well mixed substrates composed of CO2 and H2O ice, consistent with regolith-mixed CO2 ice grains formed by radiolysis. Additionally, we detected a 2.35-micron feature in some low sub-observer latitude spectra, which might result from CO formed as part of a CO2 radiolytic production cycle., Comment: Accepted in Planetary Science Journal
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- 2021
- Full Text
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4. Radiation Tolerance of Low-Cost Magnetometer for Space Applications
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Regoli, Leonardo H., Moldwin, Mark B., Raines, Connor, Nordheim, Tom A., Miller, Cameron A., Pozzi, Sara A., and Carts, Martin
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radiation ,tolerance ,Physics::Space Physics ,cost ,magnetometer ,applicatons ,Astrophysics::Earth and Planetary Astrophysics ,space ,low ,Physics::Geophysics - Abstract
Knowing the three-dimensional magnetic field configuration and dynamics in space environments is key to understand the physical processes taking place. Plasma dynamics depend on the local orientation of the magnetic field, and key quantities such as pitch angle and dynamical processes such as waves and reconnection cannot be studied without in-situ measurements of the fields. For this reason, magnetometers are one of the most important instruments for space physics-focused missions. This is true both for spacecraft and also for landed missions, particularly on atmosphere-less bodies, where the space environment interacts directly with the surface. To enable the next generation of small spacecraft and landers, sensors need to be low-cost and withstand the harsh radiation environment present in space. Here we present the latest advances in the characterization of a commercial-off-the-shelf three-dimensional magnetometer,summarizing previous and newresults from radiation tests. The sensor shows tolerance up to a total ionization dose (TID) of 300 krad, levels well beyond those typical for a low-Earth orbit mission, and compliant with those expected during a landed mission on the Jovian moon Europa.
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- 2020
5. Exploration of the Ice Giant Systems: A White Paper for NASA's Planetary Science and Astrobiology Decadal Survey 2023-2032
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Beddingfield, Chloe, Li, Cheng, Atreya, Sushil, Beauchamp, Patricia, Cohen, Ian, Fortney, Jonathan, Hammel, Heidi, Hedman, Matthew, Hofstadter, Mark, Rymer, Abigail, Schenk, Paul, Showalter, Mark, Ahrens, Caitlin, Aplin, Karen, Arney, Giada, Aslam, Shahid, Azari, Abigail, Baillié, Kevin, Barth, Erika, BENNETT, christopher, Bertrand, Tanguy, Beyer, Ross, Bramson, Ali, Bierson, Carver, Brozovic, Marina, Brueshaber, Shawn, Bruce, Emma, Burr, Devon, Burratti, Bonnie, Byrne, Paul, Cao, Xin, Cartwright, Richard, Castillo-Rogez, Julie, Chancia, Rob, Chanover, Nancy, Clark, George, Coates, Andrew, Cochrane, Corey, Collins, Geoff, Colwell, Joshua, Crary, Frank, Cruikshank, Dale, Coustenis, Athena, Ćuk, Matija, Dahl, Emma, Daubar, Ingrid, DeColibus, David, DePater, Imke, Dhingra, Rajani, Dong, Chuanfei, Elder, Catherine, Emery, Joshua, Ermakov, Anton, Ferguson, Sierra, Fletcher, Leigh, French, Robert, Golder, Keenan, González, Felipe, Gordon, Mitchell, Grava, Cesare, Grodent, Denis, Grundy, Will, Hammond, Noah, Hawkins, Emily, Hayes, Alex, Helfenstein, Paul, Helled, Ravit, Hemingway, Douglas, Hendrix, Amanda, Higgins, Chuck, Hofmann, Amy, Holler, Bryan, Holt, Timothy, Hospodarsky, George, Howett, Carly, Hsu, Hsiang-Wen, Jackman, Caitriona, Jasinski, Jamie, Jha, Devanshu, Jia, Xianzhe, Jun, Insoo, Karkoschka, Erich, Kattenhorn, Simon, Kinczyk, Mallory, Kirchoff, Michelle, Kollmann, Peter, Kumar, Kartik, Keane, James, Kampf, Sascha, Leonard, Erin, Leung, Cecilia, Lissauer, Jack, Lopes, Rosaly, Lucas, Michael, Lucchetti, Alice, Mandt, Kathleen, Marouf, Essam, Martin, Emily, Masters, Adam, McGrath, Melissa, Michaels, Tim, Mitchell, Karl, Moran, Sarah, Moses, Julianne, Nenon, Quentin, Neveu, Marc, Nimmo, Francis, Nordheim, Tom, Pajola, Maurizio, Pappalardo, Robert, Paranicas, Chris, Patthoff, Alex, Paty, Carol, Person, Michael, Peterson, Georgia, Pinilla-Alonso, Noemi, Porter, Simon, Postberg, Frank, Probst, Alena, Quick, Lynnae, Regoli, Leonardo, Rivera-Valentín, Edgard, Roatsch, Thomas, Roberge, Aki, Roberts, James, Robbins, Stuart, Rodriguez, Sébastien, Roser, Joe, Roussos, Elias, Runyon, Kirby, Scipioni, Francesca, Scully, Jennifer, Singer, Kelsi, Soderlund, Krista, Sori, Mike, Spilker, Linda, Stern, Alan, Stryk, Ted, Styczinski, Marshall, Sulaiman, Ali, Tamayo, Daniel, Thieman, Jim, Tiscareno, Matthew, Tortora, Paolo, Turtle, Elizabeth, Umurhan, Orkan, Weiss, Benjamin, White, Oliver, Search for Extraterrestrial Intelligence Institute (SETI), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
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Earth and Planetary Astrophysics (astro-ph.EP) ,Physics::Space Physics ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Physics::Atmospheric and Oceanic Physics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Ice giants are the only unexplored class of planet in our Solar System. Much that we currently know about these systems challenges our understanding of how planets, rings, satellites, and magnetospheres form and evolve. We assert that an ice giant Flagship mission with an atmospheric probe should be a priority for the decade 2023-2032.
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- 2020
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6. The Science Case for Spacecraft Exploration of the Uranian Satellites
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Cartwright, Richard J., Beddingfield, Chloe B., Nordheim, Tom, Elder, Catherine, Grundy, Will, Bramson, Ali, Sori, Michael, Pappalardo, Robert, Neveu, Marc, Burr, Devon, Ermakov, Anton, Roser, Joe, Castillo-Rogez, Julie, Showalter, Mark, Cohen, Ian, Turtle, Zibi, and Hofstadter, Mark
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Earth and Planetary Astrophysics (astro-ph.EP) ,Physics::Space Physics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Physics::Atmospheric and Oceanic Physics ,Astrophysics - Earth and Planetary Astrophysics ,Physics::Geophysics - Abstract
The five classical Uranian moons are possible ocean worlds that exhibit bizarre geologic landforms, hinting at recent surface-interior communication. However, Uranus' classical moons, as well as its ring moons and irregular satellites, remain poorly understood. We assert that a Flagship-class orbiter is needed to explore the Uranian satellites.
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- 2020
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7. The in-situ exploration of Jupiter's radiation belts (A White Paper submitted in response to ESA's Voyage 2050 Call)
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Roussos, Elias, Allanson, Oliver, André, Nicolas, Bertucci, Bruna, Branduardi-Raymont, Graziella, Clark, George, Dialynas, Kostantinos, Dandouras, Iannis, Desai, Ravindra, Futaana, Yoshifumi, Gkioulidou, Matina, Jones, Geraint, Kollmann, Peter, Kotova, Anna, Kronberg, Elena, Krupp, Norbert, Murakami, Go, Nénon, Quentin, Nordheim, Tom, Palmaerts, Benjamin, Plainaki, Christina, Rae, Jonathan, Santos-Costa, Daniel, Sarris, Theodore, Shprits, Yuri, Sulaiman, Ali, Woodfield, Emma, Wu, Xin, Yao, Zhonghua, Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
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Earth and Planetary Astrophysics (astro-ph.EP) ,Physics - Space Physics ,Physics::Space Physics ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,ComputingMilieux_MISCELLANEOUS ,Space Physics (physics.space-ph) ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Jupiter has the most energetic and complex radiation belts in our solar system. Their hazardous environment is the reason why so many spacecraft avoid rather than investigate them, and explains how they have kept many of their secrets so well hidden, despite having been studied for decades. In this White Paper we argue why these secrets are worth unveiling. Jupiter's radiation belts and the vast magnetosphere that encloses them constitute an unprecedented physical laboratory, suitable for both interdisciplinary and novel scientific investigations: from studying fundamental high energy plasma physics processes which operate throughout the universe, such as adiabatic charged particle acceleration and nonlinear wave-particle interactions; to exploiting the astrobiological consequences of energetic particle radiation. The in-situ exploration of the uninviting environment of Jupiter's radiation belts present us with many challenges in mission design, science planning, instrumentation and technology development. We address these challenges by reviewing the different options that exist for direct and indirect observation of this unique system. We stress the need for new instruments, the value of synergistic Earth and Jupiter-based remote sensing and in-situ investigations, and the vital importance of multi-spacecraft, in-situ measurements. While simultaneous, multi-point in-situ observations have long become the standard for exploring electromagnetic interactions in the inner solar system, they have never taken place at Jupiter or any strongly magnetized planet besides Earth. We conclude that a dedicated multi-spacecraft mission to Jupiter's radiation belts is an essential and obvious way forward and deserves to be given a high priority in ESA's Voyage 2050 programme., Comment: 28 pages, 3 Tables, 11 Figures
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- 2019
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8. Solar System Ice Giants: Exoplanets in our Backyard
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Rymer, Abigail, Mandt, Kathleen, Hurley, Dana, Lisse, Carey, Izenberg, Noam, Smith, Todd, Westlake, Joseph, Bunce, Emma, Arridge, Christopher, Masters, Adam, Hofstadter, Mark, Simon, Amy, Brandt, Pontus, Clark, George, Cohen, Ian, Allen, Robert, Vine, Sarah, Hansen, Kenneth, Hospodarsky, George, Kurth, Paul, Romani, William, Lamy, Laurent, Zarka, Philippe, Cao, Hao, Paty, Carol, Hedman, Matthew, Roussos, Elias, Cruikshank, Dale, Farrell, William, Fieseler, Paul, Coates, Andrew, Yelle, Roger, Parkinson, Christopher, Militzer, Burkhard, Grodent, Denis, Kollmann, Peter, McNutt, Ralph, André, Nicolas, Strange, Nathan, Barnes, Jason, Dones, Luke, Denk, Tilmann, Rathbun, Julie, Lunine, Jonathan, Desai, Ravi, Cochrane, Corey, Sayanagi, M., Postberg, Frank, Ebert, Robert, Hill, Thomas, Mueller-Wodarg, Ingo, Regoli, Leonardo, Pontius, Duane, Stanley, Sabine, Greathouse, Thomas, Saur, Joachim, Marouf, Essam, Bergman, Jan, Higgins, Chuck, Johnson, Robert, Thomsen, Michelle, Soderlund, Krista, Jia, Xianzhe, Wilson, Robert, Englander, Jacob, Burch, Jim, Nordheim, Tom, Grava, Cesare, Baines, Kevin, Quick, Lynnae, Russell, Christopher, Cravens, Thomas, Cecconi, Baptiste, Aslam, Shahid, Bray, Veronica, Garcia-Sage, Katherine, Richardson, John, Clark, John, Hsu, Sean, Achterberg, Richard, Sergis, Nick, Paganelli, Flora, Kempf, Sasha, Orton, Glenn, Portyankina, Ganna, Jones, Geraint, Economou, Thanasis, Livengood, Timothy, Krimigis, Stamatios, Szalay, James, Jackman, Catriona, Valek, Phillip, Lecacheux, Alain, Colwell, Joshua, Jasinski, Jamie, Tosi, Federico, Sulaiman, Ali, Galand, Marina, KOTOVA, Anna, Khurana, Krishan, Kivelson, Margaret, Strobel, Darrell, Radiota, Aikaterina, Estrada, Paul, Livi, Stefano, Azari, Abigail, Yates, Japheth, Allegrini, Frederic, Vogt, Marissa, Felici, Marianna, Luhmann, Janet, Filacchione, Gianrico, Moore, Luke, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
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[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2019
9. The Origin and Fate of O2 in Europa’s Ice: An Atmospheric Perspective
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Johnson, Robert E., Oza, Apurva, Leblanc, François, Schmidt, Carl, Nordheim, Tom A., Cassidy, Timothy A., Engineering Physics Program [Charlottesville], University of Virginia [Charlottesville], Department of Physics [New York], New York University [New York] (NYU), NYU System (NYU)-NYU System (NYU), Physikalisches Institut [Bern], Universität Bern [Bern], HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), and University of Colorado [Boulder]
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Earth and Planetary Astrophysics (astro-ph.EP) ,[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] ,Exospheres ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Ices ,FOS: Physical sciences ,Atmospheric evolution ,O2 ,Europa ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The early prediction and subsequent detection of an O$_2$ atmosphere on Europa, coupled with the discovery that Europa has an ocean under its ice mantle, has made this moon a prime astrobiologic target, soon to be visited by the JUICE and Europa Clipper spacecraft. In spite of the considerable number of observational, modeling, and laboratory efforts, understanding the physics leading to the observed morphology of Europa's near surface O$_2$ atmosphere has been problematic. This is the case as the observed emissions depend on the local incident plasma ion flux, the local temperature and composition of the regolith, as well as on the near surface electron temperature and density. Here we rely heavily on earlier reviews briefly summarizing the observational, laboratory and simulation efforts. Although it is agreed that radiolysis of the surface ice by the incident Jovian plasma is the ultimate source of observed O$_2$, a recent, simple model of thermal desorption from a regolith permeated with O$_2$ has changed the usual paradigm. This suggests that the observed orbital dependence of the local source of the near-surface O$_2$ atmosphere is due to thermal release of O$_2$ likely trapped on the ice grains at dangling bonds with a smaller contribution due to direct sputtering. This could also impact our understanding of the suggestion that the radiolytic products in Europa's regolith might be a source of oxidants for its underground ocean., Comment: 25 pages, 7 figures, Submitted to Space Science Reviews
- Published
- 2019
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10. Solar System Ice Giants: Exoplanets in our Backyard
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Rymer, Abigail, Mandt, Kathleen, Hurley, Dana, Lisse, Carey, Izenberg, Noam, Smith, H. Todd, Westlake, Joseph, Bunce, Emma, Arridge, Christopher, Masters, Adam, Hofstadter, Mark, Simon, Amy, Brandt, Pontus, Clark, George, Cohen, Ian, Allen, Robert, Vine, Sarah, Hansen, Kenneth, Hospodarsky, George, Kurth, William, Romani, Paul, Lamy, Laurent, Zarka, Philippe, Cao, Hao, Paty, Carol, Hedman, Matthew, Roussos, Elias, Cruikshank, Dale, Farrell, William, Fieseler, Paul, Coates, Andrew, Yelle, Roger, Parkinson, Christopher, Militzer, Burkhard, Grodent, Denis, Kollmann, Peter, McNutt, Ralph, André, Nicolas, Strange, Nathan, Barnes, Jason, Dones, Luke, Denk, Tilmann, Rathbun, Julie, Lunine, Jonathan, Desai, Ravi, Cochrane, Corey, Sayanagi, Kunio M., Postberg, Frank, Ebert, Robert, Hill, Thomas, Mueller-Wodarg, Ingo, Regoli, Leonardo, Pontius, Duane, Stanley, Sabine, Greathouse, Thomas, Saur, Joachim, Marouf, Essam, Bergman, Jan, Higgins, Chuck, Johnson, Robert, Thomsen, Michelle, Soderlund, Krista, Jia, Xianzhe, Wilson, Robert, Englander, Jacob, Burch, Jim, Nordheim, Tom, Grava, Cesare, Baines, Kevin, Quick, Lynnae, Russell, Christopher, Cravens, Thomas, Cecconi, Baptiste, Aslam, Shahid, Bray, Veronica, Garcia-Sage, Katherine, Richardson, John, Clark, John, Hsu, Sean, Achterberg, Richard, Sergis, Nick, Paganelli, Flora, Kempf, Sasha, Orton, Glenn, Portyankina, Ganna, Jones, Geraint, Economou, Thanasis, Livengood, Timothy, Krimigi, Stamatios, Szalay, James, Jackman, Catriona, Valek, Phillip, Lecacheux, Alain, Colwell, Joshua, Jasinski, Jamie, Tosi, Federico, Sulaiman, Ali, Galand, Marina, Kotova, Anna, Khurana, Krishan, Kivelson, Margaret, Strobel, Darrell, Radiota, Aikaterina, Estrada, Paul, Livi, Stefano, Azari, Abigail, Yates, Japheth, Allegrini, Frederic, Vogt, Marissa, Felici, Marianna, Luhmann, Janet, Filacchione, Gianrico, Moore, Luke, ITA, USA, GBR, FRA, and DEU
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Earth and Planetary Astrophysics (astro-ph.EP) ,Astrophysics::High Energy Astrophysical Phenomena ,Physics::Space Physics ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Atmospheric and Oceanic Physics ,Computer Science::Databases ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Future remote sensing of exoplanets will be enhanced by a thorough investigation of our solar system Ice Giants (Neptune-size planets). What can the configuration of the magnetic field tell us (remotely) about the interior, and what implications does that field have for the structure of the magnetosphere; energy input into the atmosphere, and surface geophysics (for example surface weathering of satellites that might harbour sub-surface oceans). How can monitoring of auroral emission help inform future remote observations of emission from exoplanets? Our Solar System provides the only laboratory in which we can perform in-situ experiments to understand exoplanet formation, dynamos, systems and magnetospheres., Exoplanet Science Strategy White Paper, submitted to the National Academies of Sciences, Engineering and Medicine, Space Studies Board, 9 March 2018
- Published
- 2019
11. The electric wind of Venus: A global and persistent 'polar wind'-like ambipolar electric field sufficient for the direct escape of heavy ionospheric ions
- Author
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Collinson, Glyn A., Frahm, Rudy A., Glocer, Alex, Coates, Andrew J., Grebowsky, Joseph M., Barabash, Stas, Domagal-Goldman, Shawn D., Fedorov, Andrei, Futaana, Yoshifumi, Gilbert, Lin K., Khazanov, George, Nordheim, Tom A., Mitchell, David, Moore, Thomas E., Peterson, William K., Winningham, John D., Zhang, Tielong L., Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)
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ambipolar field ,polarization electric field ,polar wind ,[SDU]Sciences of the Universe [physics] ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Venus ,ionospheric escape - Abstract
International audience; Understanding what processes govern atmospheric escape and the loss of planetary water is of paramount importance for understanding how life in the universe can exist. One mechanism thought to be important at all planets is an "ambipolar" electric field that helps ions overcome gravity. We report the discovery and first quantitative extraterrestrial measurements of such a field at the planet Venus. Unexpectedly, despite comparable gravity, we show the field to be five times stronger than in Earth's similar ionosphere. Contrary to our understanding, Venus would still lose heavy ions (including oxygen and all water-group species) to space, even if there were no stripping by the solar wind. We therefore find that it is possible for planets to lose heavy ions to space entirely through electric forces in their ionospheres and such an "electric wind" must be considered when studying the evolution and potential habitability of any planet in any star system.
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- 2016
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12. Ionization of the Venusian atmosphere from solar and galactic cosmic rays
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Nordheim, Tom, Dartnell, L.R., Desorgher, L., Coates, Andrew J., and Jones, Geraint H.
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Astrophysics::High Energy Astrophysical Phenomena ,Physics::Space Physics ,cps ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Atmospheric and Oceanic Physics - Abstract
The atmospheres of the terrestrial planets are exposed to solar and galactic cosmic rays, the most energetic of which are capable of affecting deep atmospheric layers through extensive nuclear and electromagnetic particle cascades. In the Venusian atmosphere, cosmic rays are expected to be the dominant ionization source below ∼100 km altitude. While previous studies have considered the effect of cosmic ray ionization using approximate transport methods, we have for the first time performed full 3D Monte Carlo modelling of cosmic ray interaction with the Venusian atmosphere, including the contribution of high-Z cosmic ray ions (Z=1-28). Our predictions are similar to those of previous studies at the ionization peak near 63 km altitude, but are significantly different to these both above and below this altitude. The rate of atmospheric ionization is a fundamental atmospheric property and the results of this study have wide-reaching applications in topics including atmospheric electrical processes, cloud microphysics and atmospheric chemistry.
- Published
- 2015
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