A
Akiva Bar-Nun
Researcher at Tel Aviv University
Publications - 106
Citations - 7048
Akiva Bar-Nun is an academic researcher from Tel Aviv University. The author has contributed to research in topics: Comet & Amorphous ice. The author has an hindex of 39, co-authored 106 publications receiving 6590 citations. Previous affiliations of Akiva Bar-Nun include University of Hawaii.
Papers
More filters
Journal ArticleDOI
In situ measurements of the physical characteristics of Titan's environment
Marcello Fulchignoni,Francesca Ferri,Francesco Angrilli,Andrew J. Ball,Akiva Bar-Nun,M. A. Barucci,C. Bettanini,G. Bianchini,William J. Borucki,Giacomo Colombatti,M. Coradini,Athena Coustenis,Stefano Debei,Peter Falkner,Giulio Fanti,Enrico Flamini,V. Gaborit,R. Grard,Michel Hamelin,Ari-Matti Harri,B. Hathi,Irmgard Jernej,Mark Leese,A. Lehto,P. F. Lion Stoppato,J. J. López-Moreno,T. Mäkinen,J. A. M. McDonnell,Christopher P. McKay,Gregorio J. Molina-Cuberos,Fritz M. Neubauer,Valerio Pirronello,Rafael Rodrigo,Bortolino Saggin,Konrad Schwingenschuh,Alvin Seiff,Fernando Simões,Håkan Svedhem,Tetsuya Tokano,Martin C. Towner,R. Trautner,Paul Withers,Paul Withers,John C. Zarnecki +43 more
TL;DR: The temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface were higher than expected and the extent of atmospheric electricity was also hitherto unknown.
Journal ArticleDOI
67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio
Kathrin Altwegg,Hans Balsiger,Akiva Bar-Nun,Jean-Jacques Berthelier,André Bieler,André Bieler,Peter Bochsler,Christelle Briois,Ursina Calmonte,Michael R. Combi,J. De Keyser,Peter Eberhardt,B. Fiethe,Stephen A. Fuselier,Sébastien Gasc,Tamas I. Gombosi,Kirk C. Hansen,Myrtha Hässig,Myrtha Hässig,Annette Jäckel,E. Kopp,A. Korth,Lena Leroy,Ulrich Mall,Bernard Marty,Olivier Mousis,Eddy Neefs,T. C. Owen,Henri Rème,Henri Rème,Martin Rubin,Thierry Sémon,Chia-Yu Tzou,H. Waite,Peter Wurz +34 more
TL;DR: The direct in situ measurement of the D/H ratio in the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer aboard the European Space Agency's Rosetta spacecraft is found to be (5.3 ± 0.7) × 10−4—that is, approximately three times the terrestrial value.
Journal ArticleDOI
Prebiotic chemicals—amino acid and phosphorus—in the coma of comet 67P/Churyumov-Gerasimenko
Kathrin Altwegg,Hans Balsiger,Akiva Bar-Nun,Jean-Jacques Berthelier,André Bieler,André Bieler,Peter Bochsler,Christelle Briois,Ursina Calmonte,Michael R. Combi,Hervé Cottin,Johan De Keyser,Frederik Dhooghe,Björn Fiethe,Stephen A. Fuselier,Sébastien Gasc,Tamas I. Gombosi,Kenneth C. Hansen,Myrtha Haessig,Myrtha Haessig,Annette Jäckel,E. Kopp,A. Korth,Léna Le Roy,Urs Mall,Bernard Marty,Olivier Mousis,Tobias Owen,Henri Rème,Henri Rème,Martin Rubin,Thierry Sémon,Chia Yu Tzou,James Hunter Waite,Peter Wurz +34 more
TL;DR: The presence of volatile glycine accompanied by methylamine and ethylamines in the coma of 67P/Churyumov-Gerasimenko measured by the ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) mass spectrometer demonstrates that comets could have played a crucial role in the emergence of life on Earth.
Journal ArticleDOI
A low-temperature origin for the planetesimals that formed Jupiter
Tobias Owen,Paul R. Mahaffy,Hasso B. Niemann,Sushil K. Atreya,T. M. Donahue,Akiva Bar-Nun,I. de Pater +6 more
TL;DR: It is shown that argon, krypton and xenon in Jupiter's atmosphere are enriched to the same extent as the other heavy elements, which suggests that the planetesimals carrying these elements must have formed at temperatures lower than predicted by present models of giant-planet formation.
Journal ArticleDOI
Abundant molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko.
André Bieler,Kathrin Altwegg,Hans Balsiger,Akiva Bar-Nun,Jean-Jacques Berthelier,Peter Bochsler,Christelle Briois,Ursina Calmonte,Michael R. Combi,J. De Keyser,E. F. van Dishoeck,B. Fiethe,Stephen A. Fuselier,Sébastien Gasc,Tamas I. Gombosi,Kirk C. Hansen,Myrtha Hässig,Annette Jäckel,E. Kopp,A. Korth,Léna Le Roy,Ulrich Mall,Romain Maggiolo,Bernard Marty,Olivier Mousis,Tobias Owen,Henri Rème,Martin Rubin,Thierry Sémon,Chia-Yu Tzou,J. H. Waite,Catherine Walsh,Peter Wurz +32 more
TL;DR: The observations indicate that the O2/H2O ratio is isotropic in the coma and does not change systematically with heliocentric distance, which suggests that primordial O2 was incorporated into the nucleus during the comet’s formation, which is unexpected given the low upper limits from remote sensing observations.