EGU21-9244
https://doi.org/10.5194/egusphere-egu21-9244
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Abel transform of exponential functions for planetary and cometary atmospheres with application to observation of 46P/Wirtanen and to the OI 557.7 nm emission at Mars.

Benoit Hubert1, Guy Munhoven1, Youssef Moulane2,3,4, Damien Hutsemekers2, Jean Manfroid2, Cyrielle Opitom3, Emmanuel Jehin2, Shohei Aoki1,5, Lauriane Soret1, Leonardos Gkouvelis6, and Jean-Claude Gérard1
Benoit Hubert et al.
  • 1Université de Liège, Space sciences, Technologies & Astrophysics Research (STAR) unit at the Institute of Astrophysics and Geophysics , LPAP, Liège, Belgium
  • 2Université de Liège, Space sciences, Technologies & Astrophysics Research (STAR) unit at the Institute of Astrophysics and Geophysics , OrCa, Liège, Belgium
  • 3European Southern Observatory (ESO), Chile
  • 4Oukaimeden Observatory, High Energy Physics & Astrophysics Laboratory, Cadi Ayyad University
  • 5Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
  • 6AMES Research center, Moffett Field, Mountain view, CA, USA.

Line-of-sight integration of emissions from planetary and cometary atmospheres is the Abel transform of the emission rate, under the spherical symmetry assumption. Indefinite integrals constructed from the Abel transform integral are useful for implementing remote sensing data analysis methods, such as the numerical inverse Abel transform giving the volume emission rate compatible with the observation. We obtain analytical expressions based on a suitable, non-alternating, series development to compute those indefinite integrals. We establish expressions allowing absolute accuracy control of the convergence of these series depending on the number of terms involved. We compare the analytical method with numerical computation techniques, which are found to be sufficiently accurate as well. Inverse Abel transform fitting is then tested in order to establish that the expected emission rate profiles can be retrieved from the observation of both planetary and cometary atmospheres. We show that the method is robust, especially when Tikhonov regularization is included, although it must be carefully tuned when the observation varies across many orders of magnitude. A first application is conducted over observation of comet 46P/Wirtanen, showing some variability possibly attributable to an evolution of the contamination by dust and icy grains. A second application is considered to deduce the 557.7 nm volume emission rate profile of the metastable oxygen atom in the upper atmosphere of planet Mars.

How to cite: Hubert, B., Munhoven, G., Moulane, Y., Hutsemekers, D., Manfroid, J., Opitom, C., Jehin, E., Aoki, S., Soret, L., Gkouvelis, L., and Gérard, J.-C.: Abel transform of exponential functions for planetary and cometary atmospheres with application to observation of 46P/Wirtanen and to the OI 557.7 nm emission at Mars., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9244, https://doi.org/10.5194/egusphere-egu21-9244, 2021.

Display materials

Display file

Comments on the display material

to access the discussion