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Goetz C, Behar E, Beth A, Bodewits D, Bromley S, Burch J, Deca J, Divin A, Eriksson AI, Feldman PD, Galand M, Gunell H, Henri P, Heritier K, Jones GH, Mandt KE, Nilsson H, Noonan JW, Odelstad E, Parker JW, Rubin M, Simon Wedlund C, Stephenson P, Taylor MGGT, Vigren E, Vines SK, Volwerk M. The Plasma Environment of Comet 67P/Churyumov-Gerasimenko. SPACE SCIENCE REVIEWS 2022; 218:65. [PMID: 36397966 PMCID: PMC9649581 DOI: 10.1007/s11214-022-00931-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/20/2022] [Indexed: 06/04/2023]
Abstract
The environment of a comet is a fascinating and unique laboratory to study plasma processes and the formation of structures such as shocks and discontinuities from electron scales to ion scales and above. The European Space Agency's Rosetta mission collected data for more than two years, from the rendezvous with comet 67P/Churyumov-Gerasimenko in August 2014 until the final touch-down of the spacecraft end of September 2016. This escort phase spanned a large arc of the comet's orbit around the Sun, including its perihelion and corresponding to heliocentric distances between 3.8 AU and 1.24 AU. The length of the active mission together with this span in heliocentric and cometocentric distances make the Rosetta data set unique and much richer than sets obtained with previous cometary probes. Here, we review the results from the Rosetta mission that pertain to the plasma environment. We detail all known sources and losses of the plasma and typical processes within it. The findings from in-situ plasma measurements are complemented by remote observations of emissions from the plasma. Overviews of the methods and instruments used in the study are given as well as a short review of the Rosetta mission. The long duration of the Rosetta mission provides the opportunity to better understand how the importance of these processes changes depending on parameters like the outgassing rate and the solar wind conditions. We discuss how the shape and existence of large scale structures depend on these parameters and how the plasma within different regions of the plasma environment can be characterised. We end with a non-exhaustive list of still open questions, as well as suggestions on how to answer them in the future.
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Affiliation(s)
- Charlotte Goetz
- ESTEC, European Space Agency, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle-upon-Tyne, UK
| | - Etienne Behar
- Swedish Institute of Space Physics, Box 812, 981 28 Kiruna, Sweden
- Lagrange, OCA, UCA, CNRS, Nice, France
| | - Arnaud Beth
- Department of Physics, Umeå University, 901 87 Umeå, Sweden
| | - Dennis Bodewits
- Physics Department, Leach Science Center, Auburn University, Auburn, AL 36832 USA
| | - Steve Bromley
- Physics Department, Leach Science Center, Auburn University, Auburn, AL 36832 USA
| | - Jim Burch
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 USA
| | - Jan Deca
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, 3665 Discovery Drive, Boulder, CO 80303 USA
| | - Andrey Divin
- Earth Physics Department, St. Petersburg State University, Ulianovskaya, 1, St Petersburg, 198504 Russia
| | | | - Paul D. Feldman
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Marina Galand
- Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2AZ UK
| | - Herbert Gunell
- Department of Physics, Umeå University, 901 87 Umeå, Sweden
| | - Pierre Henri
- Lagrange, OCA, UCA, CNRS, Nice, France
- LPC2E, CNRS, Orléans, France
| | - Kevin Heritier
- Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2AZ UK
| | - Geraint H. Jones
- UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT UK
- The Centre for Planetary Sciences at UCL/Birkbeck, Gower Street, London, WC1E 6BT UK
| | | | - Hans Nilsson
- Swedish Institute of Space Physics, Box 812, 981 28 Kiruna, Sweden
| | - John W. Noonan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85719 USA
| | - Elias Odelstad
- Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden
| | | | - Martin Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Cyril Simon Wedlund
- Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
| | - Peter Stephenson
- Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2AZ UK
| | | | - Erik Vigren
- Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden
| | - Sarah K. Vines
- Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723 USA
| | - Martin Volwerk
- Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
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Malik HK, Srivastava R, Kumar S, Singh D. Small amplitude dust acoustic solitary wave in magnetized two ion temperature plasma. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2020. [DOI: 10.1080/16583655.2020.1741944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Hitendra K. Malik
- Plasma Waves and Particle Acceleration Laboratory, Indian Institute of Technology Delhi, New Delhi, India
| | - Rashmi Srivastava
- Faculty of Engineering & Technology, Manav Rachna International Institute of Research and Studies, Faridabad, India
| | - Sandeep Kumar
- Department of Physics, Manav Rachna University, Faridabad, India
| | - Devi Singh
- Faculty of Engineering & Technology, Manav Rachna International Institute of Research and Studies, Faridabad, India
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Zhang H, Li D, Wurz P, Etter A, Cheng Y, Dong C, Huang W. Performance of a Low Energy Ion Source with Carbon Nanotube Electron Emitters under the Influence of Various Operating Gases. NANOMATERIALS 2020; 10:nano10020354. [PMID: 32085559 PMCID: PMC7075284 DOI: 10.3390/nano10020354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 11/30/2022]
Abstract
Low energy ion measurements in the vicinity of a comet have provided us with important information about the planet’s evolution. The calibration of instruments for thermal ions in the laboratory plays a crucial role when analysing data from in-situ measurements in space. A new low energy ion source based on carbon nanotube electron emitters was developed for calibrating the ion-mode of mass spectrometers or other ion detectors. The electron field emission (FE) properties of carbon nanotubes (CNTs) for H2, He, Ar, O2, and CO2 gases were tested in the experiments. H2, He, Ar, and CO2 adsorbates could change the FE temporarily at pressures from10−6 Pa to10−4 Pa. The FE of CNT remains stable in Ar and increases in H2, but degrades in He, O2, and CO2. All gas adsorbates lead to temporary degradation after working for prolonged periods. The ion current of the ion source is measured by using a Faraday cup and the sensitivity is derived from this measurement. The ion currents for the different gases were around 10 pA (corresponding to 200 ions/cm3 s) and an energy of ~28 eV could be observed.
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Affiliation(s)
- Huzhong Zhang
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 73000, China; (H.Z.); (Y.C.)
- Physics Institute, University of Bern, 3012 Bern, Switzerland;
| | - Detian Li
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 73000, China; (H.Z.); (Y.C.)
- Correspondence: (D.L.); (P.W.)
| | - Peter Wurz
- Physics Institute, University of Bern, 3012 Bern, Switzerland;
- Correspondence: (D.L.); (P.W.)
| | - Adrian Etter
- Physics Institute, University of Bern, 3012 Bern, Switzerland;
| | - Yongjun Cheng
- Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 73000, China; (H.Z.); (Y.C.)
| | - Changkun Dong
- Institute of Micro-Nano Structures & Optoelectronics, Wenzhou University, Wenzhou 325035, China; (C.D.); (W.H.)
| | - Weijun Huang
- Institute of Micro-Nano Structures & Optoelectronics, Wenzhou University, Wenzhou 325035, China; (C.D.); (W.H.)
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Mandt KE, Eriksson A, Beth A, Galand M, Vigren E. Influence of collisions on ion dynamics in the inner comae of four comets. ASTRONOMY AND ASTROPHYSICS 2019; 630:A48. [PMID: 31631896 PMCID: PMC6800695 DOI: 10.1051/0004-6361/201834828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
CONTEXT Collisions between cometary neutrals in the inner coma of a comet and cometary ions that have been picked up into the solar wind flow and return to the coma lead to the formation of a broad inner boundary known as a collisionopause. This boundary is produced by a combination of charge transfer and chemical reactions, both of which are important at the location of the collisionopause boundary. Four spacecraft measured ion densities and velocities in the inner region of comets, exploring the part of the coma where an ion-neutral collisionopause boundary is expected to form. AIMS The aims are to determine the dominant physics behind the formation of the ion-neutral collisionopause and to evaluate where this boundary has been observed by spacecraft. METHODS We evaluated observations from three spacecraft at four different comets to determine if a collisionopause boundary was observed based on the reported ion velocities. We compared the measured location of the ion-neutral collisionopause with measurements of the collision cross sections to evaluate whether chemistry or charge exchange are more important at the location where the collisionopause is observed. RESULTS Based on measurements of the cross sections for charge transfer and for chemical reactions, the boundary observed by Rosetta appears to be the location where chemistry becomes the more probable result of a collision between H2O and H2O+ than charge exchange. Comparisons with ion observations made by Deep Space 1 at 19P/Borrelly and Giotto at 1P/Halley and 26P/Grigg-Skjellerup show that similar boundaries were observed at 19P/Borrelly and 1P/Halley. The ion composition measurements made by Giotto at Halley confirm that chemistry becomes more important inside of this boundary and that electron-ion dissociative recombination is a driver for the reported ion pileup boundary.
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Affiliation(s)
- K E Mandt
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd., Laurel, MD 20723
| | - A Eriksson
- Swedish Institute of Space Physics, POB 537, SE-751 21, Uppsala, Sweden
| | - A Beth
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - M Galand
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - E Vigren
- Swedish Institute of Space Physics, POB 537, SE-751 21, Uppsala, Sweden
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Xu Y, Xiong B, Chang YC, Pan Y, Lo PK, Lau KC, Ng CY. A quantum-rovibrational-state-selected study of the reaction in the collision energy range of 0.05-10.00 eV: translational, rotational, and vibrational energy effects. Phys Chem Chem Phys 2017; 19:9778-9789. [PMID: 28352920 DOI: 10.1039/c7cp00937b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report detailed absolute integral cross sections (σ's) for the quantum-rovibrational-state-selected ion-molecule reaction in the center-of-mass collision energy (Ecm) range of 0.05-10.00 eV, where (vvv) = (000), (100), and (020), and . Three product channels, HCO+ + OH, HOCO+ + H, and CO+ + H2O, are identified. The measured σ(HCO+) curve [σ(HCO+) versus Ecm plot] supports the hypothesis that the formation of the HCO+ + OH channel follows an exothermic pathway with no potential energy barriers. Although the HOCO+ + H channel is the most exothermic, the σ(HOCO+) is found to be significantly lower than the σ(HCO+). The σ(HOCO+) curve is bimodal, indicating two distinct mechanisms for the formation of HOCO+. The σ(HOCO+) is strongly inhibited at Ecm < 0.4 eV, but is enhanced at Ecm > 0.4 eV by (100) vibrational excitation. The Ecm onsets of σ(CO+) determined for the (000) and (100) vibrational states are in excellent agreement with the known thermochemical thresholds. This observation, along with the comparison of the σ(CO+) curves for the (100) and (000) states, shows that kinetic and vibrational energies are equally effective in promoting the CO+ channel. We have also performed high-level ab initio quantum calculations on the potential energy surface, intermediates, and transition state structures for the titled reaction. The calculations reveal potential barriers of ≈0.5-0.6 eV for the formation of HOCO+, and thus account for the low σ(HOCO+) and its bimodal profile observed. The Ecm enhancement for σ(HOCO+) at Ecm ≈ 0.5-5.0 eV can be attributed to the direct collision mechanism, whereas the formation of HOCO+ at low Ecm < 0.4 eV may involve a complex mechanism, which is mediated by the formation of a loosely sticking complex between HCO+ and OH. The direct collision and complex mechanisms proposed also allow the rationalization of the vibrational inhibition at low Ecm and the vibrational enhancement at high Ecm observed for the σ(HOCO+).
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Affiliation(s)
- Yuntao Xu
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA.
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Abstract
AbstractThe solar wind interaction with comets is characterized by the mass-loading of the solar wind with heavy cometary ions that are produced by the ionization of neutrals in the extensive cometary coma. This mass-loading slows down the solar wind and ultimately leads to the formation of a magnetic barrier and a magnetotail. Solar wind protons disappear in the vicinity of the cometopause due to charge-exchange collisions with neutrals. The plasma and fields inside the cometopause of comets Halley and Giacobini-Zinner were observed by instruments on board several spacecraft. Several plasma populations were detected in the inner coma, including cold (less than 1 eV) and energetic (several keV or more) ions, and cold and hot electrons. The Giotto magnetometer observed a diamagnetic cavity surrounding the nucleus, which is a consequence of an outward ion-neutral drag associated with the flow of cometary neutrals past plasma frozen onto field lines in the magnetic barrier. In addition to large-scale structures, many small-scale structures in the plasma and fields have been observed in comets, including tail rays and kinks, and plasma pile-ups and depletions in the barrier. Theoretically, the existence of a very narrow layer of enhanced plasma density just inside the diamagnetic cavity boundary has been predicted. The behavior of plasma in the inner coma (within the cometopause) of an active comet is determined both by plasma processes, such as magnetohydrodynamics, and by collisional processes such as ion-neutral friction, resistivity, electron and ion thermal cooling, ion-neutral chemical reactions, and electron-ion recombination.
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Abstract
Much has been learned about the physics and chemistry of comets from the successful spacecraft encounters and intensive remote observing programs of Comets Halley and Giacobini-Zinner. Instead of being the panacea for our comet curiosity, these tantalizing “snapshots” have raised new questions, and many fundamental problems remain unsolved. To reap fuller benefits, extensive modeling is necessary to characterize the physical structure and chemical properties of the coma and to infer the composition and structure of the nucleus.
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Coates AJ, Johnstone AD, Wilken B, Jockers K, Glassmeier KH. Velocity space diffusion of pickup ions from the water group at comet Halley. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja094ia08p09983] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Puhl-Quinn P, Cravens TE. One-dimensional hybrid simulations of the diamagnetic cavity boundary region of comet Halley. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/95ja01820] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Blanford GE, Thomas KL, McKay DS. Microbeam Analysis of Four Chondritic Interplanetary Dust Particles for Major Elements, Carbon and Oxygen. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1945-5100.1988.tb00906.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bell DM, Boyle JM, Anderson SL. H+ versus D+) transfer from HOD+ to N2: mode- and bond-selective effects. J Chem Phys 2011; 135:044305. [PMID: 21806117 DOI: 10.1063/1.3615655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reactions of HOD(+) with N(2) have been studied for HOD(+) in its ground state and with one quantum of excitation in each of its vibrational modes: (001)--predominately OH stretch, 0.396 eV, (010)--bend, 0.153 eV, and (100)--predominately OD stretch, 0.293 eV. Integral cross sections and product recoil velocities were recorded for collision energies from threshold to 4 eV. The cross sections for both H(+) and D(+) transfer rise slowly from threshold with increasing collision energy; however, all three vibrational modes enhance reaction much more strongly than equivalent amounts of collision energy and the enhancements remain large even at high collision energy, where the vibration contributes less than 10% of the total energy. Excitation of the OH stretch enhances H(+) transfer by a factor of ∼5, but the effect on D(+) transfer is only slightly larger than that from an equivalent increase in collision energy, and smaller than the effect from the much lower energy bend excitation. Similarly, OD stretch excitation strongly enhances D(+) transfer, but has essentially no effect beyond that of the additional energy on H(+) transfer. The effects of the two stretch vibrations are consistent with the expectation that stretching the bond that is broken in the reaction puts momentum in the correct coordinate to drive the system into the exit channel. From this perspective it is quite surprising that bend excitation also results in large (factor of 2) enhancements of both H(+) and D(+) transfer channels, such that its effect on the total cross section at collision energies below ∼2 eV is comparable to those from the two stretch modes, even though the bend excitation energy is much smaller. For collision energies above ∼2 eV, the vibrational effects become approximately proportional to the vibrational energy, though still much larger than the effects of equivalent addition of collision energy. Measurements of the product recoil velocity distributions show that reaction is direct at all collision energies, with roughly half the products in a sharp peak corresponding to stripping dynamics and half with a broad and approximately isotropic recoil velocity distribution. Despite the large effects of vibrational excitation on reactivity, the effects on recoil dynamics are small, indicating that vibrational excitation does not cause qualitative changes in the reaction mechanism or in the distribution of reactive impact parameters.
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Affiliation(s)
- David M Bell
- Department of Chemistry, University of Utah, 315 S. 1400 E. Rm 2020, Salt Lake City, Utah 84112, USA
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Bell DM, Boyle JM, Anderson SL. H+ versus D+ transfer from HOD+ to CO2: bond-selective chemistry and the anomalous effect of bending excitation. J Chem Phys 2011; 134:064312. [PMID: 21322685 DOI: 10.1063/1.3534908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Reactions of HOD(+) with CO(2) have been studied for HOD(+) in its ground state, and with one quantum of excitation in each of its vibrational modes: (001)--predominantly OH stretch, 0.396 eV; (010)--bend, 0.153 eV; and (100)--predominantly OD stretch, 0.293 eV. Integral cross sections and product recoil velocities were recorded for collision energies from threshold to 3 eV. The cross sections for both H(+) and D(+) transfer rise with increasing collision energy from threshold to ∼1 eV, then become weakly dependent of the collision energy. All three vibrational modes enhance the total reactivity, but quite mode specifically. The H(+) transfer reaction is enhanced by OH stretch excitation, whereas OD stretch excitation has little effect. Conversely, the D(+) transfer reaction is enhanced by OD stretch excitation, while the OH stretch has little effect. Excitation of the bend strongly enhances both channels. The effects of the stretch excitations are consistent with previous studies of neutral HOD mode-selective chemistry, and can be at least qualitatively understood in terms of a late barrier to product formation. The fact that bend excitation produces the largest overall enhancement is surprising, because this is the lowest energy excitation, and is not obviously connected with the reaction coordinates for either H(+) or D(+) transfer. A rationalization in terms of the effects of water distortion on the potential surface is proposed.
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Affiliation(s)
- David M Bell
- Department of Chemistry, University of Utah, 315 S. 1400 E. Rm 2020, Salt Lake City, Utah 84112, USA
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Uselman BW, Boyle JM, Anderson SL. Multiphoton ionization vibrational state selection of H2O+, D2O+ and HDO+. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.04.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Young DT, Berthelier JJ, Blanc M, Burch JL, Bolton S, Coates AJ, Crary FJ, Goldstein R, Grande M, Hill TW, Johnson RE, Baragiola RA, Kelha V, McComas DJ, Mursula K, Sittler EC, Svenes KR, Szegö K, Tanskanen P, Thomsen MF, Bakshi S, Barraclough BL, Bebesi Z, Delapp D, Dunlop MW, Gosling JT, Furman JD, Gilbert LK, Glenn D, Holmlund C, Illiano JM, Lewis GR, Linder DR, Maurice S, McAndrews HJ, Narheim BT, Pallier E, Reisenfeld D, Rymer AM, Smith HT, Tokar RL, Vilppola J, Zinsmeyer C. Composition and Dynamics of Plasma in Saturn's Magnetosphere. Science 2005; 307:1262-6. [PMID: 15731443 DOI: 10.1126/science.1106151] [Citation(s) in RCA: 257] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.
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Affiliation(s)
- D T Young
- Southwest Research Institute, San Antonio, TX 78238, USA.
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Sessouma B, Couturier-Tamburelli I, Allouche A, Aycard JP. Molecular complexes between carbon suboxide and acetylene derivatives: a cryogenic matrix and theoretical study. Chem Phys 2002. [DOI: 10.1016/s0301-0104(02)00335-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Solar system ionospheres. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/130gm04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Abstract
Remote sensing observations and the direct sampling of material from a few comets have established the characteristic composition of cometary gas. This gas is ionized by solar ultraviolet radiation and the solar wind to form 'pick-up' ions, ions in a low ionization state that retain the same compositional signatures as the original gas. The pick-up ions are carried outward by the solar wind, and they could in principle be detected far from the coma (Sampling of pick-up ions has also been used to study interplanetary dust, Venus' tail and the interstellar medium.) Here we report the serendipitous detection of cometary pick-up ions, most probably associated with the tail of comet Hyakutake, at a distance of 3.4 AU from the nucleus. Previous observations have provided a wealth of physical and chemical information about a small sample of comets, but this detection suggests that remote sampling of comet compositions, and the discovery of otherwise invisible comets, may be possible.
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Israelevich PL, Gombosi TI, Ershkovich AI, DeZeeuw DL, Neubauer FM, Powell KG. The induced magnetosphere of comet Halley: 4. Comparison of in situ observations and numerical simulations. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999ja900371] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Bhardwaj A. On the role of solar EUV, photoelectrons, and auroral electrons in the chemistry of C(1D) and the production of C I 1931 Å in the cometary coma: A case for comet 1P/Halley. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1998je900004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Tamburelli I, Chiavassa T, Borget F, Pourcin J. Reactivity at Low Temperature of Carbon Suboxide (C3O2) with Amorphous Surface of HCl Hydrates Monitored by FTIR Spectroscopy. J Phys Chem A 1998. [DOI: 10.1021/jp972623d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- I. Tamburelli
- Physique des Interactions Ioniques et Moléculaires, UMR 6633, Equipe de Spectrométries et Dynamique Moléculaire, Boite 542, Université de Provence, F-13397 Marseille Cedex 20, France
| | - T. Chiavassa
- Physique des Interactions Ioniques et Moléculaires, UMR 6633, Equipe de Spectrométries et Dynamique Moléculaire, Boite 542, Université de Provence, F-13397 Marseille Cedex 20, France
| | - F. Borget
- Physique des Interactions Ioniques et Moléculaires, UMR 6633, Equipe de Spectrométries et Dynamique Moléculaire, Boite 542, Université de Provence, F-13397 Marseille Cedex 20, France
| | - J. Pourcin
- Physique des Interactions Ioniques et Moléculaires, UMR 6633, Equipe de Spectrométries et Dynamique Moléculaire, Boite 542, Université de Provence, F-13397 Marseille Cedex 20, France
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Lindgren CJ, Cravens TE, Ledvina SA. Magnetohydrodynamic processes in the inner coma of comet Halley. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97ja01117] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Lisse CM, Dennerl K, Englhauser J, Harden M, Marshall FE, Mumma MJ, Petre R, Pye JP, Ricketts MJ, Schmitt J, Trümper J, West RG. Discovery of X-ray and Extreme Ultraviolet Emission from Comet C/Hyakutake 1996 B2. Science 1996. [DOI: 10.1126/science.274.5285.205] [Citation(s) in RCA: 347] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- C. M. Lisse
- C. M. Lisse is in the Astronomy Department, University of Maryland, College Park, MD 20742, and NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA
| | - K. Dennerl
- K. Dennerl, J. Englhauser, J. Schmitt, and J. Trümper are at the Max-Planck-Institut für Extraterrestriche Physik, Postfach 1603, 85740 Garching, Germany
| | - J. Englhauser
- K. Dennerl, J. Englhauser, J. Schmitt, and J. Trümper are at the Max-Planck-Institut für Extraterrestriche Physik, Postfach 1603, 85740 Garching, Germany
| | - M. Harden
- M. Harden and M. J. Ricketts are in the Space and Astrophysics Division, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| | - F. E. Marshall
- F. E. Marshall, M. J. Mumma, and R. Petre are at the NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA
| | - M. J. Mumma
- F. E. Marshall, M. J. Mumma, and R. Petre are at the NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA
| | - R. Petre
- F. E. Marshall, M. J. Mumma, and R. Petre are at the NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA
| | - J. P. Pye
- J. P. Pye and R. G. West are in the Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - M. J. Ricketts
- M. Harden and M. J. Ricketts are in the Space and Astrophysics Division, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK
| | - J. Schmitt
- K. Dennerl, J. Englhauser, J. Schmitt, and J. Trümper are at the Max-Planck-Institut für Extraterrestriche Physik, Postfach 1603, 85740 Garching, Germany
| | - J. Trümper
- K. Dennerl, J. Englhauser, J. Schmitt, and J. Trümper are at the Max-Planck-Institut für Extraterrestriche Physik, Postfach 1603, 85740 Garching, Germany
| | - R. G. West
- J. P. Pye and R. G. West are in the Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
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Häberli RM, Altwegg K, Balsiger H, Geiss J. Heating of the thermal electrons in the coma of comet P/Halley. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja01191] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gombosi TI, De Zeeuw DL, Häberli RM, Powell KG. Three-dimensional multiscale MHD model of cometary plasma environments. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja01075] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Balsiger H, Altwegg K, Geiss J. D/H and18O/16O ratio in the hydronium ion and in neutral water from in situ ion measurements in comet Halley. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/94ja02936] [Citation(s) in RCA: 154] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bhardwaj A, Haider SA, Singhal RP. Consequences of cometary aurora on the carbon chemistry at comet P/Halley. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1995; 16:31-36. [PMID: 11543533 DOI: 10.1016/0273-1177(95)00190-p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Various experimental data acquired during the visit of Halley's comet in 1986 have shown that the amount of carbon produced due to photodissociation of parent carbon bearing species is not ample enough to explain the observations. This requires the presence of an additional source of atomic carbon. One of the possible source could be auroral-type activities resulting from the precipitation of high-energy "auroral electrons" of solar wind origin, the evidence of which have been inferred from many observations at comet Halley. We have developed a coupled chemistry-transport model to study the role of auroral and photoelectron impact as well as of chemistry on the modelling of carbon in the inner coma (< or = 10(4) km) of comet Halley. Our study suggest that electron impact dissociation of CO is the major source of carbon production in the inner coma, not the recombination of CO+ as suggested by earlier workers, while transport is the main loss process.
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Affiliation(s)
- A Bhardwaj
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum, India
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28
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Rème H, Mazelle C, d’Uston C, Korth A, Lin RP, Chaizy P. There is no “cometopause” at comet Halley. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/93ja00894] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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McClements KG, Dendy RO. Ion cyclotron harmonic wave generation by ring protons in space plasmas. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93ja00158] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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Goldstein BE, Goldstein R, Neugebauer M, Fuselier SA, Shelley EG, Balsiger H, Kettmann G, Ip WH, Rosenbauer H, Schwenn R. Observations of plasma dynamics in the coma of P/Halley by the Giotto Ion Mass Spectrometer. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/91ja03105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wyckoff S. Cometary constraints on the planet forming environment. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1992; 12:13-20. [PMID: 11538132 DOI: 10.1016/0273-1177(92)90148-q] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Molecular elemental and isotopic abundances of comets provide sensitive diagnostics for models of the primitive solar nebula. New measurements of the N2, NH and NH2 abundances in comets together with the in situ Giotto mass spectrometer and dust analyzer data provide new constraints for models of the comet forming environment in the solar nebula. An inventory of nitrogen-containing species in comet Halley indicates that NH3 and CN are the dominant N carriers observed in the coma gas. The elemental nitrogen abundance in the gas component of the coma is found to be depleted by a factor approximately 75 relative to the solar photosphere. Combined with the Giotto dust analyzer results for the coma dust component, we find for comet Halley Ngas + dust approximately 1/6 the solar value. The measurement of the CN carbon isotope ratio from the bulk coma gas and dust in comet Halley indicates a significantly lower value, 12C/13C = 65 +/- 9 than the solar system value of 89 +/- 2. Because the dominant CN carrier species in comets remains unidentified, it is not yet possible to attribute the low isotope ratio predominantly to the bulk gas or dust components. The large chemical and isotopic inhomogeneities discovered in the Halley dust particles on 1 mu scales are indicative of preserved circumstellar grains which survived processing in the interstellar clouds, and may be related to the presolar silicon carbide, diamond and graphite grains recently discovered in carbonaceous chondrites. Less than 0.1% of the bulk mass in the primitive meteorites studied consists of these cosmically important grains. A larger mass fraction (approximately 5%) of chemically heterogeneous organic grains is found in the nucleus of comet Halley. The isotopic anomalies discovered in the PUMA 1 Giotto data in comet Halley are probably also attributable to preserved circumstellar grains. Thus the extent of grain processing in the interstellar environment is much less than predicted by interstellar grain models, and a significant fraction of comet nuclei (approximately 5%) may be in the form of preserved circumstellar matter. Comet nuclei probably formed in much more benign environments than primitive meteorites.
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Affiliation(s)
- S Wyckoff
- Department of Physics and Astronomy, Arizona State University, Tempe 85287-1504, USA
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Verheest F, Lakhina GS. Nonresonant low-frequency instabilities in multibeam plasmas: Applications to cometary environments and plasma sheet boundary layers. ACTA ACUST UNITED AC 1991. [DOI: 10.1029/91ja00254] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Breus TK, Krymskii AM, Lundin R, Dubinin EM, Luhmann JG, Yeroshenko YG, Barabash SV, Mitnitskii VY, Pissarenko NF, Styashkin VA. The solar wind interaction with Mars: Consideration of Phobos 2 mission observations of an ion composition boundary on the dayside. ACTA ACUST UNITED AC 1991. [DOI: 10.1029/91ja01131] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Chaizy P, Rème H, Sauvaud JA, d'Uston C, Lin RP, Larson DE, Mitchell DL, Anderson KA, Carlson CW, Korth A, Mendis DA. Negative ions in the coma of comet Halley. Nature 1991. [DOI: 10.1038/349393a0] [Citation(s) in RCA: 186] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Lishawa CR, Dressler RA, Gardner JA, Salter RH, Murad E. Cross sections and product kinetic energy analysis of H2O+–H2O collisions at suprathermal energies. J Chem Phys 1990. [DOI: 10.1063/1.458852] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Coates AJ, Wilken B, Johnstone AD, Jockers K, Glassmeier KH, Huddleston DE. Bulk properties and velocity distributions of water group ions at comet Halley: Giotto measurements. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/ja095ia07p10249] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sckopke N, Paschmann G, Brinca AL, Carlson CW, Lühr H. Ion thermalization in quasi-perpendicular shocks involving reflected ions. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/ja095ia05p06337] [Citation(s) in RCA: 186] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Coates AJ, Johnstone AD, Kessel RL, Huddleston DE, Wilken B, Jockers K, Neubauer FM. Plasma parameters near the comet Halley bow shock. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/ja095ia12p20701] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Keller CN, Cravens TE. Plasma density enhancement at the comet Halley diamagnetic cavity boundary. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/ja095ia11p18755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Greenberg JM, Zhao N, Hage J. Chemical evolution of interstellar dust, comets and the origins of life. ANNALES DE PHYSIQUE 1989; 14:103-31. [PMID: 11542180 DOI: 10.1051/anphys:01989001402010300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
It now appears that the chemical evolution of the pre-solar system interstellar dust ensures that a major fraction of comets is in the form of complex organic molecules at least partially of a prebiotic nature and that the submicron interstellar dust preserves its chemical integrity as result of forming a very tenuous low density comet structure whose solid matter occupies approximately 1/5 of the total volume. This low density micro structure further provides a physical basis for comets bringing a significant fraction of the original interstellar organic molecules to the earth unmodified by the impact event. Finally, the evidence for a large number of comet collisions with the early earth ensured that the major organic molecular budget on the earth's surface was "continuously" supplied along with water well before 3.8 billion years ago which is the earliest date for life. The chemistry and morphological structure of a comet nucleus as an aggregate of interstellar dust is used to provide comparisons with a variety of comet Halley results: the density of the nucleus and of the dust; the dust cloud model and its consequences on the production of C+ and CN in the coma by small organic grains; the surface albedo and the low nucleus heat conductivity and high surface temperature; the appearance of 10(-14) g and 10(-17) g dust particles along with higher masses; the mass spectra of dust and infrared spectroscopy as evidence for complex organic grain mantles and of very small (approximately 0.01 micrometer) carbonaceous and silicate grains; the appearance of small grains resulting from breakup of larger grains. The cosmic ray dosage of a comet nucleus during its 4.5 billion years in the Oort cloud appears to be many orders of magnitude less than the dosage of the preaggregated interstellar dust by ultraviolet photons except perhaps in the outer few meters of the nucleus of a new comet. The heat conductivity calculated for aggregated dust is certainly less than 10(-4) that of crystalline ice. This, in combination with the interstellar dust microstructure, provide a basis for showing that solar heating of the interior of a nucleus is lower than previously estimated.
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Affiliation(s)
- J M Greenberg
- Laboratory Astrophysics, University of Leiden, The Netherlands
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Goldstein BE, Altwegg K, Balsiger H, Fuselier SA, Ip WH, Meier A, Neugebauer M, Rosenbauer H, Schwenn R. Observations of a shock and a recombination layer at the contact surface of comet Halley. ACTA ACUST UNITED AC 1989. [DOI: 10.1029/ja094ia12p17251] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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46
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Khare BN, Thompson WR, Chyba CF, Arakawa ET, Sagan C. Organic solids produced from simple C/H/O/N ices by charged particles: applications to the outer solar system. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1989; 9:41-53. [PMID: 11537360 DOI: 10.1016/0273-1177(89)90362-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
CH4, CO, and CO2 are all potential one-carbon molecular repositories in primitive icy objects. These molecules are all found in the Comet Halley coma, and are probable but, (except for CH4 detected on Triton and Pluto) undetected subsurface constituents in icy outer solar system objects. We have investigated the effects of charged particle irradiation by cold plasma discharge upon surfaces of H2O:CH4 clathrate having a 200:1 ratio, as well as upon ices composed of H2O plus C2H6 or C2H2 (sometimes plus NH3) which are also plausible constituents. These materials color and darken noticeably after a dose 10(9) - 10(10) erg cm-2, which is deposited rapidly (< or = 10(4) yr.) in solar system environments. The chromophore is a yellowish to tan organic material (a tholin) which we have studied by UV-VIS reflection and transmission, and IR transmission spectroscopy. Its yield, -1 C keV-1, implies substantial production of organic solids by the action of cosmic rays and radionuclides in cometary crusts and interiors, as well as rapid production in satellite surfaces. This material shows alkane bands which Chyba and Sagan have shown to well match the Halley infrared emission spectrum near 3.4 microns, and also bands due to aldehyde, alcohol and perhaps alkene/aromatic functional groups. We compare the IR spectral properties of these tholins with the spectra of others produced by irradiation of gases and ices containing simple hydrocarbons.
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Affiliation(s)
- B N Khare
- Laboratory for Planetary Studies, Cornell University, Ithaca, NY 14853
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Khare BN, Thompson WR, Murray BG, Chyba CF, Sagan C. Solid organic residues produced by irradiation of hydrocarbon-containing H2O and H2O/NH3 ices: infrared spectroscopy and astronomical implications. ICARUS 1989; 79:350-361. [PMID: 11542162 DOI: 10.1016/0019-1035(89)90082-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Methane clathrate (CH4 nH2O)--expected in cometary nuclei, in outer Solar System satellites, and perhaps in interstellar grains--as well as ices prepared from other combinations of CH4, C2H6, or C2H2 with H2O (and sometimes with NH3) were irradiated at 77 degrees K by plasma discharge. CH4 clathrate and other H2O/hydrocarbon ices color and darken noticeably after a dose approximately 10(8) to approximately 10(9) erg cm-2 over a period of 1-10 hr. Upon evaporation of the now yellowish to tan irradiated ices, a colored solid film adheres to the walls of the reaction vessel at room temperature. Transmission measurements of these organic films were made from 2.5 to 50 micrometers wavelength. The residue left after CH4 nH2O irradiation exhibits IR bands which we tabulate and identify with alkane, aldehyde, alcohol, and perhaps alkene and substituted aromatic functional groups. Aldehydes are especially well indicated, and may be related to recent claims of polyoxymethylene (H2CO)n in the coma of Comet Halley. Spectra presented here are compared with previous studies of UV or proton-irradiated, nonenclathrated hydrocarbon-containing ices may be useful for interpreting infrared features found in the spectra of comets and interstellar grains.
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Affiliation(s)
- B N Khare
- Laboratory for Planetary Studies, Cornell University, Ithaca, New York 14853, USA
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Abstract
It is speculated that life originated in a small, shallow body of water containing concentrated prebiotic organic feedstocks, inorganic compounds, and catalytic agents in a diversity of microenvironments. This pond was formed by an improbable, fortuitous soft-landing of a cometary nucleus, or fragment thereof, on the surface of a suitable planet with an atmosphere in an appropriate thermodynamic state, such as Earth.
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Affiliation(s)
- B C Clark
- Planetary Sciences Laboratory, Martin Marietta Astronautics, Denver, CO 80201
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