I. Decade-scale surface-atmosphere interaction
2005: 30.9 AU, 34° sub-solar lat2015: 32.8 AU, 49° sub-solar latFarther at 0.2 AU/year distance,More northerly at 1.5 °/year.
0
20
40
60
30 35 40 45 50
1990
2000
2010
20202030
2040
2050
2060
2070
2080
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2100
Distance from Sun (AU)
1990 20002010
2020
2030
2040
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2060
20702080
209021002110
26
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42
0.001 0.01 0.1 1 10 100
Radio occultation observableN2 α-β transition
40 ( . 2004) K Tryka et al
UVS occultation observable
Global atmosphere
Stellar occultationobservable
( )Surface Temperature K
( )Surface Pressure µbar
01234567
1850 1900 1950 2000 2050 2100 2150year
2005-2015, distance increases by 6%, insolation decreases by 12%. Simplest models have temperature decreasing by 3% (~1.2K),for the pressure nearly halving.
Sicardy et al. 2003, Nature 424
Elliot et al. 2003, Nature 424
perihelion
Hansen and Paige fig 3 (high thermal inertia)
Hansen and Paige 1996, Icarus 120
1000 1200year
Hansen and Paige fig 4 (moderate thermal inertia)
perihelion
1000 1200year
Hansen and Paige fig 7 (low thermal inertia)
perihelion
1000 1200year
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
Darkening of ices following sublimation Thermal inertiaOld, frost-covered winter pole coming into sunlight
II. Distinguishing seasonal models with observations
Changes in lightcurve mean and amplitude can be due to volatile transport or changing viewing.
14.9
15.1
15.3
15.5
15.60 0.2 0.4 0.6 0.8 1
phase (0.75-East Longitude/360))
Stern et al. 1988, Icarus 75Buie et al. 1997, Icarus 125 1992/93
1982.2
1975.2
1964.4
1954.8
Douté et al 1999, Icarus 142
N2
CH4
CO
Spectra on the surface absorption in reflected sunlight is diagnostic of the volatiles on Pluto's surface, including their grain size, mixing state, and temperature. 0.8-2.5 µm range includes N2, CH4, and CO. Shorter wavelengths include weak CH4 bands, and CH4 and tholins have absorption at 3.3 µm (See Olkin 55.02).
1000 1200year
N2 frost temperature
60 µm brightness temperature1300 µm brightess temperature
Hansen and Paige 1996, Icarus 120
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
Occultations are the most sensitive and direct measure of changes in atmospheric pressure.
Young 2004, BAAS
2005 Jul 11 03:36:14 UTC313.2 (Sicardy 49.05, Young 55.04, Gulbis 55.05)
2006 Jun 12 16:21:49 UTP384.2
2006 Oct 31 2:30:29 UTP415
2007 May 12 4:42:24 UTP456
III. Some words of warning...
Young et al. 2001, AJ 121
Grundy & Buie 2001, Icarus 153
Young 55.03, Buie 49.03
0
0.5
1
1.5
2
2006 2007 2008 2009 2010Date
Non-secular time-dependent effects on visible albedo—rotation and possible opposition surges
Longitudinal change is much larger than the tentative secular variation (green vs. red dots) in CH4 1.66 µm band
Grundy and Buie 2001,Icarus 153.
1995
1998
Lellouch et al. 2000, Icarus 147
Thermal rotational lightcurves have higher amplitudes thanthe expected seasonal change.
.2 Jy
.6 Jy .6 Jy
.3 Jy
0 Jy
.8 Jy
.3 Jy
.8 Jy
IV. New Horizons spacecraft to Pluto; flight 2006-2015
PERSI Remote Sensing Package
Objectives:MVIC: Global geology and geomorphology. Stereo and terminator images. Refine radii and orbits. Search for rings and satellites. Search for clouds and hazes.LEISA: Global composition maps, high resolution composition maps, temperatures from NIR bands.ALICE: UV airglow and solar occultation to characterize Pluto’s neutral atmosphere. Search for ionosphere, H, H2, and CxHy. Search for Charon’s atmosphere.
REX Radio Experiment
Objectives:•Profiles of number density,temperature, and pressure inPluto ’s atmosphere, includingconditions at surface.•Search for Pluto’s ionosphere.•Search for atmosphere andionosphere on Charon.•Measure masses and radii ofPluto and Charon, and massesof flyby KBOs.•Measure disk- averagedmicrowave brightnesstemperatures (4.2 cm) ofPluto and Charon.
SWAP Solar Wind Plasma Sensor
Objectives:•Slowdown of the solar wind,as a diagnostic of Pluto’s atmospheric escape rate.•Solar wind standoff•Solar wind speed•Solar wind density•Nature of interaction of solar wind and Pluto’s atmosphere (distinguish magnetic, cometary, and ionospheric interactions)
PEPSSI Pluto Energetic Particle Spectrometer
Objectives:•Measure energetic particles from Pluto’s upper atmosphere,as a diagnostic of Pluto’s atmospheric escape rate.
LORRI Long Range Reconnasance Imager
Objectives• Far-side maps• High-resolution closest approach images, including terminator and stereo imaging.
Summary
• We expect Pluto to undergo seasonal change in the next decade
• Observations can constrain models of voalatile transport in the outer solar system
• Beware spatial-temporal confusion!• Long time-base observations support
and are supported by the planned New Horizons mission to Pluto