Research Highlight

Insights into Titan's ionosphere

doi:10.1038/nindia.2011.110 Published online 26 July 2011

New insights into the ionosphere of Titan, Saturn's largest Moon, might help researchers design better space probes. Researchers have found vital information on the size and mass density of the charged aerosols in Titan's ionosphere. This will help them better understand the data beamed back by spacecraft and in turn make better probes.

Titan is continuously bombarded with solar radiation. Extreme ultraviolet radiation ionizes molecules in its upper atmosphere to release electrons and ions. These ions and electrons transfer their charge to the aerosols in the ionosphere.

Despite studies, there is a dearth of comprehensive view on these charged aerosols. The Cassini spacecraft has identified some ionospheric heavy ions as aromatic hydrocarbons, acetylene and nitrile polymers or fullerenes. These heavy ions are believed to be aerosols.

Relying on data gleaned by Cassini-Huygens probe, the researchers calculated the charge state, size and mass density of the aerosol particles.

They report that at 950 km and 1120 km in the ionosphere, aerosols of sizes from 0.5 to 32 nm have not more than one charge. Their model predicted up to two charges for 64 nm aerosols with a higher concentration of negatively charged aerosols. The results have shown aerosol particle density of 1–10 kg per cubic metre at the studied altitudes.

"The study throws new light on the charge, size and density of the aerosol particles setting a benchmark for future observations and analysis of data," says lead researcher Marykutty Michael.

The authors of this work are from: Department of Civil Engineering, Indian Institute of Technology Kanpur; NASA Goddard Space Flight Center, Greenbelt, and Space Science and Engineering Division, Southwest Research Institute, San Antonio, USA; and Mullard Space Science Laboratory, University College London, London, UK.


  1. Michael, M. et al. High-altitude charged aerosols in the atmosphere of Titan. Planet. Space. Sci. 59, 880-885 (2011) | Article | ADS |