University of Kansas

Titan Studies

Image courtesy of NASA/JPL-Caltech.

Titan Studies at the University of Kansas

Titan is the largest satellite of Saturn with an orbital distance from that planet of 20 Saturn radii (RS), at which distance it will usually find itself within Saturn's outer magnetosphere, where it will interact with the magnetospheric plasma. Titan is, after Jupiter's satellite Ganymede, the second largest satellite in our solar system. Titan possesses an extensive neutral atmosphere consisting mainly of molecular nitrogen and methane. Titan also has an ionosphere due to the photoionization of the neutrals by solar extreme ultraviolet photons or due to ionization by energetic electrons associated with Saturn's magnetosphere. Complex photochemistry takes place in the upper atmosphere and ionosphere due to the presence of methane in the atmosphere and the existence of energy inputs such as solar ultraviolet radiation and energetic external plasma.

The current view is that Titan does not have a significant intrinsic magnetic field; hence, the external plasma impinges directly on Titan's upper atmosphere and ionosphere. The atmosphere and ionosphere of Titan act together to create an obstacle to the flow of Saturn's magnetospheric plasma that is incident on that satellite. Usually, Titan is located inside Saturn's magnetosphere and the external plasma is the magnetospheric plasma; but occasionally solar wind conditions will be such that Titan will be outside the magnetopause and Titan will interact with the solar wind.

Most of our early knowledge about Titan and its magnetospheric interaction derived from data gathered by the Voyager 1 spacecraft when it encountered Titan on November 12, 1980. Titan was located within the Saturnian magnetosphere on this occasion. Voyager approached to within a radial distance of 6900 km from Titan, and downstream of the satellite with respect to the motion of the magnetospheric plasma.

On July 1, 2004 the Cassini Orbiter successfully entered orbit around Saturn, passing within about 30,000 km of its surface and passing through the ring plane outside the main rings. During this "Saturn Orbit Insertion" (SOI) event many instruments measured the properties of the rings of Saturn. The Orbiter first encountered Titan on October 26, 2004, when it approached within 1200 km of the surface. The Huygens probe separated from the Orbiter in December 2004 and parachuted to the surface in January 2005, and while doing so taking measurements and sending images back to Earth (via a link through the Orbiter). The Orbiter, with its extensive set of field and particle instruments, encountered Titan several more times. The Space Physics group at KU is participating in this mission with a team member on the Ion and Neutral Mass Spectrometer (INMS).

During SOI as the spacecraft flew over Saturn's A-ring, the INMS measured oxygen ions which indicated the existence of a tenuous ring atmosphere. During the October 2004 encounter with Titan, the INMS made the first in situ measurements of the neutral atmosphere of this satellite, and during the April 2005 "T5" encounter the INMS observed a rich and complicated ion composition in Titan's atmosphere.

The Space Physics group at the University of Kansas has undertaken a number of studies of the upper atmosphere and ionosphere of Titan and its interaction with Saturn's magnetosphere. This website includes links to a number of papers on these topics.

Publications:

(Links to some journals--in particular AGU and other Wiley journals--may not work with some browsers, such as Safari. AGU/Wiley links should all work with Firefox. Apologies for the inconvenience.)

2006-Present

  • Solar Cycle Variations in Ion Composition in the Ionosphere of Titan, H. Madanian, T. E. Cravens, M. S. Richard, N. J. T. Edberg, J. H. Westlake, J.-E. Wahlund, and J. H. Waite Jr., Journal of Geophysical Research, 121, 8013, doi:10.1002/2015JA022274, 2016. Abstract with link to full article.

  • An Empirical Approach to Modeling Ion Production Rates in Titan's Ionosphere I: Ion Production Rates on the Dayside and Globally, M. Richard, T. E. Cravens, C. Wylie, D. Webb, Q. Chediak, R. Perryman, K. Mandt, J. Westlake, J. H. Waite Jr., I. Robertson, B. Magee, and N. Edberg, Journal of Geophysical Research, 120, 1264, doi:10.1002/2013JA019706, 2015. Abstract with link to full article.

  • An Empirical Approach to Modeling Ion Production Rates in Titan's Ionosphere II: Ion Production Rates on the Nightside, M. Richard, T. E. Cravens, C. Wylie, D. Webb, Q. Chediak, K. Mandt, J. H. Waite Jr., A. Rymer, C. Bertucci, A. Wellbrock, A. Windsor, and A. J. Coates, Journal of Geophysical Research, 120, 1281, doi:10.1002/2014JA020343, 2015. Abstract with link to full article.

  • The Role of Ion-Molecule Reactions in the Growth of Heavy Ions in Titan’s Ionosphere, J. H. Westlake, J. H. Waite Jr., N. Carrasco, M. Richard, and T. E. Cravens, Journal of Geophysical Research, 119, 5951, doi:10.1002/2014JA020208, 2014. Abstract and link to full article.

  • The Orientation of Titan's Dayside Ionosphere and Its Effects on Titan's Plasma Interaction, S. A. Ledvina, S. Brecht, and T. E. Cravens, Earth Planets Space, 64, 207, doi:10.5047/eps.2011.08.009, 2012. Abstract and link to full article.

  • The Observed Composition of Ions Outflowing from Titan, J. H. Westlake, C. P. Paranicas, T. E. Cravens, J. G. Luhmann, K. E. Mandt, H. T. Smith, D. G. Mitchell, A. M. Rymer, M. E. Perry, J. H. Waite Jr., and J.-E. Wahlund, Geophysical Research Letters, 39, L19104, doi:10.1029/2012GL053079, 2012. Abstract and link to full article.

  • Energetics of Titan's Ionosphere: Model Comparisons with Cassini Data, M. Richard, T. E. Cravens, I. P. Robertson, J. H. Waite, Jr., J.-E. Wahlund, F. J. Crary, and A. J. Coates, Journal of Geophysical Research, 116, A09310, doi:10.1029/2011JA016603, 2011. Abstract and link to full article.

  • Dynamical and Magnetic Field Time Constants for Titan's Ionosphere--Empirical Estimates and Comparisons with Venus, T. E. Cravens, M. Richard, Y.-J. Ma, C. Bertucci, J. Luhmann, S. Ledvina, I. P. Robertson, J.-E. Wahlund, K. Agren, J. Cui, I. Muller-Wodarg, J. H. Waite, M. Dougherty, J. Bell, and D. Ulusen, Journal of Geophysical Research, 115, A08319, doi:10.1029/2009JA015050, 2010. Abstract and link to full article.

  • Structure of Titan's Ionosphere: Model Comparisons with Cassini Data, I. P. Robertson, T. E. Cravens, J. H. Waite Jr., R. V. Yelle, V. Vuitton, A. J. Coates, J. E. Wahlund, K. Agren, K. Mandt, B. Magee, and M. S. Richard, Planetary and Space Science, 57, 1834, doi:10.1016/j.pss.2009.07.011, 2009. Abstract and link to full article.

  • Model-Data Comparisons for Titan's Nightside Ionosphere, T. E. Cravens, I. P. Robertson, J. H. Waite, Jr., R. V. Yelle, V. Vuitton, A. J. Coates, J.-E. Wahlund, K. Agren, M. S. Richard, V. De La Haye, A. Wellbrock, and F. N. Neubauer, Icarus, 199, 174, doi:10.1016/j.icarus.2008.09.005, 2009. Abstract and link to full article.

  • Diurnal Variations of Titan's Ionosphere, J. Cui, M. Galand, R. V. Yelle, V. Vuitton, J.-E. Wahlund, P. Lavvas, I. C. F. Mueller-Wodarg, T. E. Cravens, W. T. Kasprzak, and J. H. Waite Jr., Journal of Geophysical Research, 114, A06310, doi:10.1029/2009JA014228, 2009. Abstract and link to full article.

  • Energetic Ion Precipitation at Titan, T. E. Cravens, I. P. Robertson, S. A. Ledvina, D. Mitchell, S. M. Krimigis, and J. H. Waite, Jr., Geophysical Research Letters, 35, 03103, doi:10.1029/2007GL032451, 2008. Abstract and link to full article.

  • Titan's Corona: The Contribution of Exothermic Chemistry, V. De La Haye, J. H. Waite Jr., T. E. Cravens, A. F. Nagy, R. E. Johnson, S. Lebonnois, and I. P. Robertson, Icarus, 191, 236, doi:10.1016/j.icarus.2007.04.031, 2007. Abstract and link to full article.

  • Cassini Ion and Neutral Mass Spectrometer Data in Titan's Upper Atmosphere and Exosphere: Observation of a Suprathermal Corona, V. De La Haye, J. H. Waite Jr., R. E. Johnson, R. V. Yelle, T. E. Cravens, J. G. Luhmann, W. T. Kasprzak, D. A. Gell, B. Magee, F. Leblanc, M. Michael, S. Jurac, and I. P. Robertson, Journal of Geophysical Research, 112, A07309, doi:10.1029/2006JA012222, 2007. Abstract and link to full article..

  • The Process of Tholin Formation in Titan's Upper Atmosphere, J. H. Waite Jr., D. T. Young, T. E. Cravens, A. J. Coates, F. J. Crary, B. Magee, and J. Westlake, Science, 316, 87, doi:10.1126/science.1139727, 2007. Abstract and link to full article.

  • Comparisons Between MHD Model Calculations and Observations of Cassini Flybys of Titan, Y. Ma, A. F. Nagy, T. E. Cravens, I. V. Sokolov, K. C. Hansen, J.-E. Wahlund, F. J. Crary, A. J. Coates, and M. K. Dougherty, Journal of Geophysical Research, 111, A05207, doi:10.1029/2005JA011481, 2006. Abstract and link to full article.

  • The Composition of Titan's Ionosphere, T. E. Cravens, I. P. Robertson, J. H. Waite Jr., R. V. Yelle, W. T. Kasprzak, C. N. Keller, S. A. Ledvina, H. B. Niemann, J. G. Luhmann, R. L. McNutt, W.-H. Ip, V. de la Haye, I. Muller-Wordag, J.-E. Wahlund, V. A. Anicich, and V. Vuitton, Geophysical Research Letters, 33, L07105, doi:10.1029/2005GL025575, 2006. Abstract and link to full article.

2000-2005

  • Titan's Ionosphere: Model Comparisons with Cassini Ta Data, T. E. Cravens, I. P. Robertson, J. Clark, J.-E. Wahlund, J. H. Waite Jr., S. A. Ledvina, H. B. Niemann, R. V. Yelle, W. T. Kasprzak, J. G. Luhmann, R. L. McNutt, W.-H. Ip, V. de la Haye, I. Muller-Wordag, D. T. Young, and A. J. Coates, Geophysical Research Letters, 32, no. 12, L12108, doi: 10.1029/2005GL023249, 2005. Abstract and link to full article.

  • Ion Distributions in Saturn's Magnetosphere Near Titan, S. A. Ledvina, T. E. Cravens, and K. Kecskemety, Journal of Geophysical Research, 110, A6, A06211, doi:10.1029/2004JA010771, 2005. Abstract and link to full article.

  • Ion Neutral Mass Spectrometer Results from the First Flyby of Titan, J. H. Waite Jr., H. Niemann, R. V. Yelle, W. T. Kasprzak, T. E. Cravens, J. G. Luhmann, R. L. McNutt, W.-I. Ip, D. Gell, V. de la Haye, I. Muller-Wordag, Brian Magee, N. Borggren. S. L. Ledvina, Greg Fletcher, E. Walter, R. Miller, S. Scherer, Rob Thorpe, Jing Xu, Bruce Block, and Ken Arnett, Science, 308, 982, doi:10.1126/science.1110652, 2005. Abstract and link to full article.

  • 3-D Global MHD Model Prediction of the First Close Flyby of Titan by Cassini, Y.-J. Ma, A. F. Nagy, T. E. Cravens, I. G. Sokolov, J. Clark, and K. C. Hansen, Geophysical Research Letters, 31, doi:10.1029/2004GL021215, 2004. Abstract and link to full article.

  • Ambient Ion Distributions in Saturn's Magnetosphere Near Titan During a Non-Voyager Type Interaction, S. A. Ledvina, J. G. Luhmann, and T. E. Cravens, Advances in Space Research, 33, 221, doi:10.1016/j.asr.2003.05.010, 2004. Abstract with link to full article.

  • Titan's Induced Magnetosphere, S. A. Ledvina, J. G. Luhmann, S. H. Brecht, and T. E. Cravens, Advances in Space Research, 33, 2092, doi:10.1016/j.asr.2003.07.056, 2004. Abstract with link to full article.

  • The Ionosphere of Titan: An Updated Theoretical Model, T. E. Cravens, J. Vann, J. Clark, J. Wu, C. N. Keller, and C. Brull, Advances in Space Research, 33, 212, doi:10.1016/j.asr.2003.02.012, 2004 (special issue on Planetary Atmospheres, Ionospheres and Plasma Interactions, edited by E. Kallio and H. Shinagawa). Abstract with link to full article.

  • Ion Trajectories in Saturn's Magnetosphere Near Titan, S. A. Ledvina, T. E. Cravens, A. Salman, and K. Kecskemety, Advances in Space Research, 26, 1691, doi:10.1016/S0273-1177(00)00075-2, 2000. Abstract with link to full article.

Prior to 2000

See our Cassini website for more information and publications.

Return to Space Physics and Plasma Astrophysics Home Page.

Last modified April 7, 2017
Tizby Hunt-Ward
tizby@ku.edu