Key science questions

Here are the key science questions that have been identified in relation to the Planetary Atmospheres and Surfaces theme:

1. What are the physical characteristics of the atmospheres (T, P, haze, clouds, winds) ? Spectra, polarization, spectral models
2. What is the nature and composition of the surface: rocky, liquid, icy ? Spectra, polarization, spectral models
3. What is the time (and seasonal) variability of those features ? Spectra, polarization, spectral models
4. What is the internal structure of those planets? Magnetosphere, planetary models
5. What are the signatures for life ? Input from the biology community

The following is the information needed to address those questions:

• Bulk planetary composition, internal structure:
  • Radius + mass -> density
  • Atmospheric composition -> (distinguish Neptune-like planet from terrestrial one, any trace of volcanic gases? Etc.)
• Molecular composition of the atmosphere:
  • Most abundant/with strongest signature molecules could be found at low/medium spectral resolution, both VIS and IR.
  • Less abundant/weaker signature/chemical gradients/temporal variations NEED higher spectral resolution (> 100), very good S/N, short integration time (few hours/days).
• Vertical Thermal structure:
  • IR, NEED higher spectral resolution (> 100), very good S/N, short integration time (few hours).
• Dynamics
  • IR, NEED Very short integration times + repeated observations to detect temporal variability.
• Clouds/aerosols
  • All wavelengths
  • Easier to identify in VIS with the contribution of polarization
  • Very short integration times + repeated observations to detect temporal variability
• Albedo/Surface
  • VIS
  • Polarization can make a crucial contribution
• Magnetic field, upper atmosphere
  • UV, ionized species, very high Res.
  • R, H3+ very high Res.
• Biosignatures
  • As 2b, need to detect chemical gradients, temporal variations.