Simulating spectra of Jupiter’s atmosphere in ASIMUT-ALVL

M. Cisneros1, S. Robert1,2, J. Erwin2, A. C. Vandaele2, C. Lauzin1, M. Lopez-Puertas3

1 Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain
2 Planetary Aeronomy, Royal Belgian Institute for Space Aeronomy (BIRA-IASB)
3 Solar System, Institute of Astrophysics of Andalusia (IAA)
miriam.cisneros@uclouvain.be

Although several missions, space observatories and ground-based telescopes have studied Jupiter’s atmosphere and continue providing information about its vertical structure and its distribution around the planet, lots of questions still remain open.1-2 We are particularly interested on the composition of Jupiter’s atmosphere, specifically on the H2O and CH4 contents, which are the most abundant species in the troposphere as a whole, after H2 and He.1 Therefore, we would like to perform simulations of different test-cases with respect to the viewing geometries of the next space mission to the Jovian system: the Jupiter ICy Moons Explorer (JUICE), mainly concerning the VIS-NIR channel of the Moons And Jupiter Imaging Spectrometer (MAJIS).

ASIMUT-ALVL is a Radiative Transfer (RT) code developed at BIRA-IASB that has been extensively used to characterize Mars and Venus atmospheres.3-10 This tool is able to perform forward model simulations and atmospheric spectrum retrievals in nadir and limb geometries. However, it still needs to be adapted to properly include Jupiter’s atmosphere. Some of the changes that need to be done are the implementation of Jupiter’s physical parameters, the addition of the Rayleigh scattering contribution due to the dominant atmospheric species H2 and He, and the treatment of the Collision-Induced Absorption (CIA) due to H2-H2 and H2-He molecular systems. Moreover, aerosols represent a significant contribution in the spectra of the atmosphere, and the microphysical parameters for the water ice cloud and the different hazes that can be found in the atmosphere, need to be defined.

So far, the main radiative contributions to the spectra between 0.5 µm and 2.5 µm were simulated and finally validated through comparison with previous works 11-12. These contributions include the CH4 absorption bands, and the aerosols. The methodology ensures that each contribution is well-understood and correctly implemented into ASIMUT-ALVL before assessing the performances of the MAJIS VIS-NIR channel to characterize the vertical structure of the Jovian atmosphere. In this poster, I will describe the already validated radiative contributions and the challenges we faced for their implementation.

References:

  1. Mc Grath, M. A., et al., Cambridge University Press. 2004, 59-77.
  2. MAJIS Team, JUICE Definition Study Report. 2014.
  3. Montmessin, F., et al., Icarus. 2017, 297, 195-216.
  4. Vandaele, A.C., et al., Optics Express. 2013, 21(18), 21148.
  5. Vandaele, A.C., et al., Adv. Space Res. 2016, 57, 443-458.
  6. Vandaele, A.C., et al., Icarus. 2016, 272, 48-59.
  7. Vandaele, A.C., et al., Icarus. 2017, 295, 1-15.
  8. Vandaele, A.C., et al., Planet. Space Sci. 2015, 119, 233-249.
  9. Neefs, E., et al., Applied Optics. 2015, 54(28), 8494-8520.
  10. Robert, S., et al., Planet. Space Sci. 2016, 124, 94-104.
  11. López-Puertas, M., et al., The Astronomical Journal. 2018, 156.4, 169.
  12. Guerlet, S., et al., Icarus. 2020, 351, 113935.