Transcript You Have a Date with Pluto: July 14, 2015

NEW HORIZONS
A Journey To The Pluto System,
And Beyond
Adriana Ocampo
[email protected]
Pluto’s Discovery
Pluto was discovered in JanuaryFebruary 1930, by Clyde Tombaugh
at Lowell Observatory, Arizona.
 Pluto is a Small, Distant World
 <1% Mars’s Max Apparent Diameter (0.1 arcsec)
 And 50,000 times fainter than Mars (V~14)
How Did
WeHORIZONS
Get To Do This?
NEW
The New Horizons
Team
Persistence Does Pay
NEW HORIZONS
1 Astronomical Unit (AU) = meter stick
for Astronomers
1AU = 92 955 807.3 miles
30-40 AU to Pluto
Scientific Payload
Instruments:
 REX radio science & radiometry
 RALPH VIS/IR imaging & spectroscopy
 ALICE UV imaging spectroscopy
 LORRI High-resolution imager
 SWAP plasma spectrometer
 PEPSSI energetic particle spectrometer
 SDC EPO Student Dust Counter
At Kennedy Space Center:
November 2005
New Horizons Firsts
 First mission to Pluto
 First since launch Voyager in 1977 to an unexplored planet
 First mission to explore a iced dwarf double planet
 First mission to study Kuiper Belt Objects
 Fastest space mission ever launched
 First planetary mission to carry a student built instrument
Planets Turn Out
To Come In Many Sizes
A Lone Misfit?
The Old View:
4 Terrestrial Planets
4 Giant Planets
1 Misfit Pluto
Hardly!
Misfit Not, Pluto’s Abound
The New View:
4 Terrestrial Planets
4 Giant Planets
Perhaps 1000 Dwarf Planets
LOTS OF PLANETS!
Best HST Images
HST Observations (1994):
 Strong Surface Variegation
 Polar Features
 Stern, Buie, & Trafton (1997)
True Color Map
(Young et al.)
Pluto’s Composition
 First detected in 1985 and 1988
by a clear refractive
signature, seen in stellar
occultations; the surface pressure
is ~10 μbar.
 N2, CO, & CH4, plus trace photochemical species.
 Evidence for haze and/or
temperature T(z) struture.
 Strong seasonal effects are
expected.
 The atmosphere is likely
hydrodynamically escaping,
several km of ices lost in 4 Gyr.
 CH4 discovered 1976.
 N2 and CO ices were
discovered in the 1990s.
 The CH4 and CO
distribution is patchy.
 N2 dominates ~10:1.
Pluto’s surface contains
at least three volatiles,
each with different
physiochemical
properties.
And At Least
Five Moons
+
P4=Kerberos
P5=Styx
PLUTO’s MOONS
TO SCALE
Satellite Origin Like
Earth
A giant impact origin for PlutoCharon was first suggested in the
1980s (McKinnon 1984, 1989).
Numerical models seem incapable
of plausibly producing Charon
otherwise (Stern, McKinnon, &
Lunine 1997; Canup 2005).
The giant impact was further
strengthened by the discoveries of
Nix and Hydra in co-planar orbits to
Charon.
Flight Plan
2007: Jupiter Flyby
C/A Date
Range
28 Feb 2007
32 RJupiter
Jupiter science included studies of Jovian
meteorology, satellite geology and composition,
Auroral phenomena, and magnetospheric physics.
Jupiter Objectives
Volcanoes and Rings
Then,
Farewell Jupiter
Pluto -63 days and counting!
 Jan-Mar: Observatory Phase
 April: Begin Encounter
 14 July: Closest Approach
 Aug-Mid-2016: Downlink
At Closest Approach
Hydra
•
•
•
•
Charon-Earth
Occultation
14:20:09
15:00
Pluto-Earth
Occultation
12:52:30
Charon
14:00
13:00
Pluto
Charon-Sun
Occultation
14:17:50
S/C trajectory time ticks: 10 min
Occultation: center time
Position and lighting at Pluto C/A
Distance relative to body center
Sun
Earth
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
CLOSEST APPROACH 13.78 km/s
7:50 AM EDT
8509 miles
31,317MPH
11:00
Nix
Charon
Nix
Hydra
New Horizons Trajectory
Orbit Period
a
6.4 d
19,571 km
24.9 d
48,675 km
38.2 d
64,780 km
Revolutionary Datasets
Are In Store
Six months of encounter science.
Exceed Hubble resolution for months.
Map Pluto and all its satellites.
Make composition maps of Pluto & Charon.
Map surface temperature fields.
Measure Pluto’s escape rate.
Assay Pluto’s atmospheric structure and
composition.
 Determine if either Pluto or Charon differentiated.
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But the most exciting
discoveries will likely be
the ones we don’t anticipate.
So Anticipate
Dramatic Results!
Triton from Voyager
Triton & Pluto
At Best HST
Resolution
Then On To KBOs
2017-2021
Explore Pluto with New Horizons: July 14. 2015
http://pluto.jhuapl.edu/
BACKUP SLIDES
Beyond Pluto:
KBO 2017-2019
The Kuiper Belt is a
disc-shaped region
• of icy objects
beyond the orbit of
Neptune -- billions
of kilometers from
our sun.
• Pluto and Eris are
the best known of
these icy worlds.
• There may be
hundreds more of
these ice dwarfs
planets out there
• Oort cloud region of
long term comets
32
DON’T JUDGE THIS BOOK
BY ITS COVER
From the Densities of Pluto & Charon,
One Can Derive Crude Interior Models
Pluto is a primarily
rocky, not icy body!
PLUTO’S LARGE MOON:
CHARON
 Charon was discovered, by accident, in July 1978 by Jim Christy
of the U.S. Naval Observatory.
 Charon is in synchronous orbit ~19,400 km from Pluto, and spinspin-orbit locked with a 6.4 day period.
 Charon’s surface is covered in H2O-ice; there is as yet no
detected atmosphere.
0.9 arc-sec
INSTRUMENT
PAYLOAD
PAYLOAD
REDUNDANCY