1
Artist Impression (A. Schaller)
Oort Cloud
100,000 AU
50 AU
Kuiper Belt
Pluto’s Orbit
Sedna’s Orbit
Asteroid Belt
5 AU
Planetary Region of Solar System Compared to the Oort Cloud
2
Discover Magazine (Nov 2004)
As of Dec 3, 2014
Explore a whole
new region of the
Solar System we
didn’t even know
existed until the
1990s
Pluto
30 AU
http://www.minorplanetcenter.net/iau/lists/OuterPlot.html
3
Pluto & Charon in Context
Updated from Wikipedia
4
Best Images of Pluto TODAY
HST/FOC: 200 km/pixel
(1994)
HST/ACS-PC: 540 km/pix
(2002-2003)
5
Hubble: Feb 1994
Charon
Pluto
6
http://hubblesite.org/newscenter/archive/releases/1994/17/
Hubble: July 2012
Styx
Kerberos
7
http://hubblesite.org/newscenter/archive/releases/2012/32/
South Pole facing Sun
(1948)
Pluto Disc. by C. Tombaugh (1930)
(1928)
Northern Winter
Southern Summer
(1969)
S
Northern Autumn
Southern Spring
(1907)
Charon Disc.
by J. Christy
(1978)
(1887)
Perihelion (1990)
Aphelion (1866)
Equator facing Sun
Fastest motion
Equator facing Sun
Slowest motion
49.3AU
29.5AU
(2093)
Northern Summer
Southern Winter
Northern Spring
Southern Autumn
(2010)
New Horizons
Fly-By (2015)
33AU
(2072)
N
(2031)
North Pole facing Sun
(note: this presentation adopts N/S pole designation; not IAU standard)
(2052)
8
Emily Lakdawalla after Candy Hansen
Our best maps of Pluto’s surface come from
1994 and 2002-2003 HST observations
N. Pole Brighter
than S. Pole
N2 rich
Old
tholin+H20
?
Bright area Lon=180° (anti-Charon)
CO rich
0° Lon = side that faces Charon
New Horizons has specific observations to
map the bright and dark patches.
http://hubblesite.org/newscenter/archive/releases/2010/06/image/i/
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Pluto Surface
N2 , CH4 , CO
Bright surface frosts of N2, CH4, CO, and C2H6 produce albedo of ~55%
0.8
Geometric Albedo
0.6
CH4
0.4
CH4
0.2
CH4
CO
CH4
N2
CH4
CH4
CH4 CH4
CH4
CH4
0.0
1.5
1.6
1.7
1.8
1.9
2.0
2.1
Wavelength (microns)
2.2
CH4 CH4
CO
2.3
2.4
2.5
Douté et al 1999, Icarus 142
New Horizons LEISA Spectrometer
1.220-2.49 μm (R~240) and 2.09-2.229 μm (R~550)
Hi Res channel centered around 2.149 μm N2 feature
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Charon Surface
Crystalline H2O , most likely NH3
NH3
H2O
NH3
Merlin et al. 2010 Icarus 210, 930
New Horizons LEISA Spectrometer covers a
large wavelength range: 1.220-2.49 μm
(R~240) and 2.09-2.229 μm (R~550)
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Pluto & Charon in Context
Cyan points have CH4
Brown, AREPS 2012
Brown, AREPS 2012
deMeo, 2013 Pluto Conference
12
Pluto’s surface is 40-60 K but
occultation data implies
upper atmosphere is ~100 K
(warmer than Triton’s 60K).
Radius (km)
Radius (km)
Atmosphere doubled in size from 1988 to 2002
Rp = 1160km
(assumed)
Sicardy et al 2003
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REX
PEPSSI &
SWAP
Alice
New Horizons Instrument
Suite
Ralph
RTG
LORRI
(cover on)
Star Tracker
SDC
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Dec 4, 2014
http://pluto.jhuapl.edu/mission/
whereis_nh.php
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Closest Approach Geometry July 14, 2015
Sun
0.24° Earth
Hydra
•
•
•
•
Charon-Earth
Occultation
14:20:09
15:00
Pluto-Earth
Occultation
12:52:30
S/C trajectory time ticks: 10 min
Occultation: center time
Position and lighting at Pluto C/A
Distance relative to body center
Red Line New Horizons Trajectory
Charon
14:00
Sun
Earth
13:00
Pluto
Charon-Sun
Occultation
14:17:50
0.24°
12:00
Pluto-Sun
Occultation
12:51:28
Charon C/A
12:04:00
29,432 km Pluto C/A
13.87 km/s 11:50:00
13,695 km
Hydra C/A 13.78 km/s
12:04:28
77,571 km
11:00
Nix
Nix C/A
11:13:01
22,013 km
Pluto
N Pole
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•
•
•
•
•
Dec 6, 2014 Final Wakeup
Jan-Apr 2015: Observatory Phase
May 2015: Better than HST
Closest Approach: Tuesday 14 July
Downlink: Through late-2016
New Horizons Project Website
http://pluto.jhuapl.edu/
Project Countdown & PPOD
http://seeplutonow.com
NASA’s New Horizons Website
http://www.nasa.gov/mission_pages/new
horizons/main/
Alex Parker
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