January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young 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 Pressure Extinction Refractivity Bending angle => Flux Position in shadow =>

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

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

T0T0

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

January 11, 2007 Workshop 3e Zone, Nantes. Leslie Young Effects of an example haze layer Haze dramatically changes the lower temperature profile. Brings dT/dr closer to a dry adiabat. Consider the effects of sudden haze onset at 1263 km with a scale height of 15 km. R (km) v. T (K) R (km) v. dT/dr (K/km) dry 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 N 2 surface vapor pressure equilibrium, this implies an increase in surface temperature of K. –Pressures consistant between 2002 and 2006 Pluto’s upper atmosphere (model fit): –Non-isothermal. dT/dr = ±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 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