Pluto & Charon
Exploring Distant worlds
Pluto is just one of
hundreds of objects in
The Kuiper Belt the
Hundreds of small icy
worlds to explore - the keys
to understanding the origin
of our solar system
Pluto was discovered in
1930 by Clyde
Tombaugh at the Lowell
Observatory, Arizona
Tombaugh spent many nights
at the telescope, many days
looking at photographic plates looking for objects that move
relative to the stars
The Planets at a Glance
Small
Inner
Rocky
Planets
Misfit
Planets
- Ice
Dwarves
Giant
Outer
Gas
Planets
Pluto orbits the Sun on an elliptical path, tilted from the plane of
the planets, between 30 and 50 times the distance of the Earth
from the Sun.
In 1978 Jim Christy discovered that Pluto has a moon
Charon
Even with a good telescope, the Earth’s atmosphere makes
tiny Pluto look very fuzzy
Seeing is Understanding
Pluto at
Best HST Resolution
Triton at
Best HST Resolution
Earth’s Moon at the
Same Resolution
HST = Hubble Space Telescope
Hubble’s Best Pictures
Smoothed and modeled images
Temperature:
40 Kelvin
-233 Celsius
-340 F
Surface = Ice
+ ... ???
1988 Stellar
occultation by
Pluto
Gradual decrease in
starlight -> atmosphere
Po~3 nanobar, T~50K
The solar wind interacts with Pluto’s
atmosphere like a comet
Spectroscopy Reveals Composition
Triton
Voyager 2
1989
2 New Moons!
Fall 2005
• Discovered with HST
• Diameter ~100 km
• Circular, resonant orbits
You need a big
antenna to send the
data back from
distant Pluto
Camera
New Horizons - Student Dust Counter
Designed, Built, Tested,
Operated, Analyzed by
Students at CU
SDC Detector Assembly
Wiring Rail &
Top Cover
S/C Mounting Feet
Detector Support
Panel
37 Pin Intra-Harness Connector
PVDF Detector
2005: Testing
New Horizons Mission
2006 Launch
Launch date:
Jan 11-Feb 14, 2006
NH
Star 48B
S/C launch mass:
465 kg
Pluto arrival:
2015-2020
Atlas V
New Horizons
to be launched on
Atlas 551 with Star
48B upper stage
from Cape Canaveral,
Florida
2006 Baseline Mission Design
Pluto-Charon Encounter Geometry – Arrival July 14, 2015
Charon-Earth Occultation
14:37:35
Pluto-Earth Occultation
13:10:44
Charon
14:00
Pluto
13:00
Charon-Sun Occultation
14:35:29
Sun
Earth
0.24°
Pluto-Sun Occultation
13:09:54
12:00
Charon C/A
12:33:47
26,673 km
13.87 km/s
Pluto C/A
12:20:00
11,095 km
13.77 km/s
New Horizons Mission
Triton
• Approach pictures better
than Hubble for 150 days
before arrival
• Total cost ~$725 M over 10
years
~ 1 Starbucks coffee per taxpayer
What will we see? Our
best guess is that Pluto
will be like Neptune’s
moon Triton
… or probably not??
The Kuiper Belt
Neptune
U
S
J
>1000 Objects Discovered Since 1992
..... and counting
The Kuiper Belt
• 1000s of objects - Ice (+ rock)
• Dark (radiation? organics?)
• 100 - 1000 miles across
• Source of comets?
• Boundary at 50 AU?
• Scattered during outward migration of Neptune?
........ are there other, bigger planets out there?
Planet X?
Xena &
Gabrielle
- 10th Planet?
All the more
reason to get out
there and explore!
Let’s keep exploring!
http://pluto.jhuapl.edu