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					               Pluto occultation 2006 June 12
               from Australia & New Zealand
          Leslie Young, Eliot Young, Catherine Ruhland, Catherine Olkin (SwRI)
          Richard French (Wellesley College)
          Marc Buie (Lowell Observatory)
          Jeff Regester (Greensboro Day School, NC)
          Kevin Shoemaker (Shoemaker Labs, Longmont CO)
          Martin George (Launceston Planetarium, Tasmania)
          John Broughton (Reedy Creek, Australia)
          Grant Christie,Tim Natusch (Auckland Observatory)
          Ross Dickie, Peter Jaquiery, Graham Blow (RASNZ)
          Dave Gault (Hawkesbury Heights, Australia)
          Blair Lade (Stockport Observatory, Australia)




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                             Occultation Overview




Temperature
            => Refractivity => Bending => Flux
Pressure                                  Position in shadow
                                angle
Extinction


January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                         Occultation:
                  Reconstructed Shadow Path




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                       Reedy Creek 0.51 m (20")
                          John Broughton




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
  Anglo-Australian Telescope 4-m (163 ")
     Dick French, Kevin Shoemaker




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
           Hawkesbury Heights 0.25 m (10")
                    Dave Gault




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
        Stockport Observatory 0.51 m (20")
                   Blair Lade




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                    Longford Farm 0.36 m (14")
                     Eliot Young, Jeff Register




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
         Auckland Observatory 0.36 m (14")
            Grant Christie, Tim Natusch




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
              Carter Observatory 0.41 m (16")
                 Marc Buie, Trina Ruhland




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
              Farm near Wanaka, 0.36 m (14")
      Leslie Young, Cathy Olkin, Peter Jaquirey, Ross Dickie




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                                Geometric Solution




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                                Geometric Solution




January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                                    Change in Shadow Radius:
                                          1988 to 2002: 2.74 ± 1.36 km/yr (increase)
                                          2002 to 2006: 1.17 ± 4.31 km/yr (consistent with
                                            no change)



January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
   Frame Rate: 10 Hz
   SNR per point: 62
   SNR per 60 km: 331
   GPS-based absolute timing accuracy better than 100 µsecond.
   Spikes are resolved, differ in detail between ingress/egress


January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                   T0




                                                                2006 AAT      2006 AAT     2006 AAT     1988 KAO
                                                                 Ingress       Egress        Avg           Avg
                                           T0 (K)               100.0±4.2     106.4±4.6    103.9±3.2    104.0±7.3
                                           P0 (µbar)            1.76±0.14     1.95±0.15    1.86±0.10    0.83±0.11
                                           dT0/dr (K/km)       -0.113±0.045 -0.082±0.051 -0.086±0.033 -0.040±0.052
                                           r1 (km)             1286.8±10.6   1287.1±37.1   1273.6±7.1   1215.8±1.3
                                                          -1
                                           2 (1000xkm )         2.7±0.5       3.0±0.5      3.0±0.4      4.1±0.3
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young         16.6±1.7      15.9±1.8      15.9±1.1     24.6±4.2
                                           H2
                 Lower Atmosphere Inversion
                              (Ref: Elliot, Person and Qu 2003)




 •   Small Planet Case
 •   No Ray Crossing
 •   Geometric Optics
 •   Clear Atmosphere

January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                    Immersion




       R (km) v. T (K)                                      R (km) v. dT/dr (K/km)




                                                          dry
                                                          adiabat

January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                                                              Emersion




       R (km) v. T (K)                                      R (km) v. dT/dr (K/km)




                                                          dry
                                                          adiabat

January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
        Monte Carlo-Based Error Estimates

                                  R (km) v. T (K)
                                  - Nominal Case
                                  - 1-sigma env.




  • Monte Carlo errors based on 100 simulated lightcurves with
    appropriate noise.
  • The Temperature Inversions: Similar overall shape, similar
    wiggles, but largest errors (up to ±18 K) above the
    temperature inversion at 1240 km.
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
             Effects of an example haze layer
Consider the effects
of sudden haze                                                   R (km) v. T (K)
onset at 1263 km
with a scale height
of 15 km.




                                                                 •   Haze dramatically
                                                                     changes the lower
                                                                     temperature profile.
                                                                 •   Brings dT/dr closer to a
         dry                                                         dry adiabat.
                                        R (km) v. dT/dr (K/km)
         adiabat
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young
                                          Conclusions
  •    Pluto's bulk atmosphere (geometry):
        – 1988 to 2006, pressure has increased by 0.98 ± 0.09 µbar, a factor of 2.17±0.21
        – For N2 surface vapor pressure equilibrium, this implies an increase in surface
          temperature of 1.2-1.7 K.
        – Pressures consistant between 2002 and 2006
  •    Pluto’s upper atmosphere (model fit):
        – Non-isothermal. dT/dr = -0.127±0.028 K/km
        – Average (103.9±3.2 K) same as 2002 (104±2 K, isothermal fit),
          and 1988 (104.0±7.3 K).
        – 99.4±3.1 K (ingress, 30.0 S, summer), 105.5±3.5 K (egress, 53.2 N, winter)
          dispite ~1500 less insolation averaged over the winter latitude,
          so not tied to insolation (in a straightforward way)
  •    Pluto’s lower atm, clear assumption (inversion):
        – As in 1988 & 2002, not isothermal.
        – Temperature inversion around 1210 - 1220 km.
        – Ingress & Egress are qualitatively similar, but the density perturbations differ in detail.
  •    Pluto’s lower atm, haze assumption (inversion, removing haze from model fit)
        – Top of haze poorly constrained.
        – Temperature purturbations qualitatively similar to those seen on Earth, Jupiter, Titan
January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young

				
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