Experimental light scattering by small planetary particles

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Experimental light scattering by small planetary
particles
Hester Volten, Olga Muñoz, Joop Hovenier, Wim
van der Zande, Rens Waters
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Planetary particles (Martian analog)
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Small mineral particles occur e.g. in
Planetary atmospheres Comets and asteroids To
interpret e.g. observational data, we need the
scattering properties of mineral particles -
shape - refractive index - size
distribution
SCATTERING MATRIX
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Scattering matrix
The scattering by a sample of randomly oriented
particles can be described by a scattering matrix
total intensity

linear polarization
circular polarization
Stokes vector
scattering matrix
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Experimental Setup
laser
detector
monitor
sample
ring
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Mars dust analogs

• Palagonite
• basaltic glass
• reff 5.6 mm

Hematite Fe2O3 reff 0.4 mm
Highly different refractive indices Palagonite
Re(m) 1.5, Im(m) 10-3-10-4 Hematite Re(m)
3.0, Im(m) 10-1-10-2
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Scattering matrix Palagonite
-F12/F11
F22/F11
F11
F34/F11
F44/F11
F33/F11
Scattering angle (degrees)
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Results Palagonite and Hematite (preliminary!)

-F12/ F11
F22/F11
F11
F34/F11
F44/F11
F33/F11
Scattering angle (degrees)
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Concluding Remarks

• Palagonite scatters similar to other silicates.
• Hematite shows a quite different scattering
  behavior, most probably due to a very high
  refractive index.
• Thanks to these beautiful Martian analogs we are
  starting to disentangle refractive index effects
  on the scattering matrix.

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Plans for the future

• More, extreme refractive indices
• Different shapes
• e.g. aggregates
• Apply the data to
• planetary (Martian)
• observations and models.