Moons of Uranus, Neptune, Pluto!

October 2012!

.!So many moons, so little time…!

The Top Five Moons!

Io Europa Triton Enceladus Titan!

small moons!•  <300 km across!•  not spherical!•  probably asteroids

captured in ‘mini solar nebulae’!

Many retrograde orbits!Outermost highly inclined!

Today

Uranus – 27 moons!

1986 = Voyager!

Uranus mid-size moons !Is the lack of large moons related to

Uranus being tipped on its side?!

1500 km!

Miranda!500 km!

A moon that was broken up and put

back together?!

Regular moons orbit around

Uranus’ equator!!

Change in orientation over

84-year orbit!

Neptune – 13 Moons !

2700 !km!

1989 = Voyager!

Triton - Moon of Neptune!Retrograde orbit!

Captured?!

Pluto's closest cousin!

!"#$%&$'(')*+%%,'-%.'$/%01%

-'2345%

The Dwarfs !!

Or! !

Trans-Neptune Objects!!

Or! !

Kuiper Belt Objects!!

Eris !The Kuiper Belt!!•  Different sizes and colors!

•  Bigger than the largest asteroids!

Pluto is sometimes closer to the Sun than Neptune - is it an escaped moon of Neptune?!

Orbital calculations show Pluto and Neptune’s orbits to be in 3:2 resonance !

Pluto now!

Neptune and Pluto dance together !- but never get close!

!

Pluto : What We Know 6 %,0)7(*%$((089#:(%$%;%<=>?@%,0)7(*%0A#(0A$.%0%;%BC%.$)@%>DE%*$:2%'2F01%6 %G'1:9'A:(%8$20'.%'H%I=JEC>J<%.:*/%6 K$A/01*%0/%>=<J%L%<=<I%)%#MNJ%%%%%%%%%%%O://%;%O$:217PD??%6 %Q20)71%/R2H:#$%H2'/1/%'H%S>@%T,D@%TU@%:A.%T>,I%%82'.R#$%:(F$.'%'H%V??W%6 %,0)7(*%X:20$):1$.%/R2H:#$%N%F20)71%:A.%.:23%2$)0'A/%6 %G$..0/7%0A%#'('2@%82'F:F(*%.R$%1'%/R2H:#$%'2):A0#/%6 %Y$AR'R/@%X:20:F($%:1M'/87$2$%N%M'/1(*%S>%%%%%%%%6 %>NB<%ZF:2/%:1%17$%/R2H:#$%[%)'0A)%R8\%

Hubble Image

Variation with time??!

Hubble: May 2005!

Hubble: June 2011! Hubble: July 2012!

USNO/Flagstaff: July 1978 !

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Binary Planet System!Mass of Pluto ~ 6 x Mass of Charon!

http://pluto.jhuapl.edu/science/everything_pluto/10_binary_planet.php!

Pluto & Charon

both spin and orbit every 6.4

days!

Spin-Orbit Phase Lock!

"M8:#1%b'2M:9'A%'H%T7:2'A%c%(03$%'R2%O''A%

New Horizons!Mission To Pluto !

Eyes & Ears Rex!

SWAP!

PEPSSI!

Lorri!

Ralph!

Alice!

SDC!

New Horizons - Student Dust Counter!

Designed, Built, Tested, Operated, Analyzed by

Students at CU!

New Horizons: To Pluto and Beyond

Pluto-Charon July 2015

KBOs 2016-2020

Jupiter System Feb-March 2007

Launch Jan 2006

Pluto

Charon

0.24°

Sun!Earth!

13:00

14:00

12:00

Pluto-Charon Encounter Geometry Arrival July 14, 2015

Pluto C/A 12:20:00 11,095 km 13.77 km/s

Charon C/A 12:33:47 26,673 km 13.87 km/s

Pluto-Sun Occultation 13:09:54

Pluto-Earth Occultation 13:10:44

Charon-Sun Occultation 14:35:29

Charon-Earth Occultation 14:37:35

Images better than Hubble >150 days !before arrival!

Will Pluto Look Like Triton? Endogenically Active Dwarf Planet? -Powered by radiogenic heat? -Easily deformed, mobile surface ices?

Pluto’s Small Satellites?

Object r,km ", g cm-3!

!Metis 21.5!Amalthea 83.5 857 ± 99!Thebe 49.3!!Prometheus 43.1 480 ± 90!Pandora 40.7 490 ± 60!Epimetheus 58.1 640 ± 62!Janus 89.5 630 ± 30!Hyperion 135 544 ± 50!Phoebe 106.5 1638 ± 33!!Puck ~80!!Mathilde 26.5 1300 ± 200 !Eros 8.5 2640 ± 20!Ida 15.7 2600 ± 500!

Crater morphology is affected by porosity, sweeping of!co-orbital materials, and fracture history!

Provided by Peter Thomas!

New Horizons Resolution on Pluto (Simulations of MVIC context imaging vs LORRI high-resolution "noodles”)

0.6 km/pix!

0.1 km/pix!

The Best We Can Do Now!

HST/ACS-PC: 540 km/pix!

Pluto’s Atmosphere:

Stellar Occultations

Sicardy et al. 2003: 2x increase in atmospheric density between 1988 and 2002

Pluto Encounter Geometry

To Sun The NH spacecraft is targeted to fly through the shadows of Pluto and Charon.!

The blue plane depicts the!ecliptic.!

Where is it safe?

Potential Hazard for New Horizons

•  The discovery of multiple satellites in the system raises the concern that debris associated with those satellites might pose a risk to the New Horizons spacecraft as it passes through the Pluto system.

Lagrange Points L1 – L5

The figure at the right depicts the geometry of the Pluto system as the NH spacecraft penetrates the Pluto-Charon orbital plane. The origin is at the center of Pluto. Pluto is depicted by the magenta solid circle, and Charon by the black solid circle. Both are drawn to scale. The dashed magenta (Pluto) and black circles (Charon) show the Roche limits. The barycenter is at the small purple x. Particles near the 1:2 Mean Motion Resonance (MMR) with Charon follow the dotted blue curves in a frame with the Pluto-Charon line fixed (Winter, priv. comm.). Inside the green dot-dash circle is stable for prograde, non-resonant orbits; inside the red dash-dots circle is stable for retrograde, non-resonant orbits (Stern et al. 1994; Dones 2011). The black curve is the NH trajectory, solid above the plane, dashed below. The aim point for the NH S/C at the time of the orbital plane crossing is marked by the red X. The black line between Pluto’s center and the NH trajectory marks the time of closest approach (CA) to Pluto. Although depicted schematically here, there are no stable Lagrange points for the Pluto-Charon binary. *The dotted cyan curve is a circle centered on the barycenter, at Charon’s

distance from the barycenter. The dotted black curve is a circle centered on Pluto at Charon’s distance from Pluto. Which is best for SHBOT?

Potential Hazard for New Horizons Spacecraft

Safe Haven Bail Out Trajectory Design #3

42!

Let’s keep exploring!!!http://pluto.jhuapl.edu!!