Giant Planets
Mark Marley (NASA Ames) for the Planetary Decadal Survey Giant Planets Subpanel
Tuesday, December 22, 2009 1 GPP Membership
Reta Beebe Brigette Hesman Wayne Richie NMSU NRAO NASA Langley atmos. dynamics atm chemistry engineer John Casani William Hubbard Kunio Sayanagi JPL University of Arizona CalTech engineer, NAE interiors dynamics, theory John Clarke Mark Marley Amy Simon-Miller Boston University NASA Ames NASA Goddard aurorae, magnetos. exoplanets panel vice-chair Heidi Hammel Phil Nicholson Space Science Cornell University Institute rings panel chair
Tuesday, December 22, 2009 2 Today • Some highlights of giant planet science in the past decade that impact future exploration goals (personal perspective, neglecting Cassini) • Stressing: Connection to brown dwarfs & 400+ exoplanets • Decadal process • whitepapers • mission studies • key technologies • community input
Tuesday, December 22, 2009 3 Solar System Jovian Planets Serve as Waypoints in a Continuum of Objects
Tuesday, December 22, 2009 4 TiO FeH K H2O H2O 6 H2O M6.5 V 10 L5 H O T.5 CO 2 Jupiter
K M6 4 CIA H2 10 CH4 CH4 CH4 CH4 CH4 L5 CH4 NH3
2 10 T5 CH4 (1.30µm) x Constant ! f NH
! 3 / ! f ! 100 Jupiter CH4
1 2 3 4 5 6 7 8 9 10 Wavelength (µm) Marley & Leggett (2009)
Tuesday, December 22, 2009 5 oklo.org
Tuesday, December 22, 2009 6 15 ) • Transiting planets 10Earth reveal a continuum of M, R • Microlensing suggests
Radius (R Neptunes are 5 common
0.1 1000
Charbonneau et al. (2009) Mass (MEarth)
Tuesday, December 22, 2009 7 Some Highlights and Questions
Tuesday, December 22, 2009 8 signature of planethood? vary with mass?
Owen et al. (1999)
Tuesday, December 22, 2009 9 What are Saturn’s noble gas abundances and isotope ratios?
Marty et al. (2009) Tuesday, December 22, 2009 10 Saturn’s Evolution
He phase separation
Fortney et al. (2006)
Tuesday, December 22, 2009 11 How well do we understand thermal evolution?
• Young hot planets? • Role of clouds? • Compositional gradients? • Soon hundreds of directly images young planets.
HR8799 b, c, d Marois et al. (2008)
Tuesday, December 22, 2009 12 Solar System Stratospheres
Earth Titan
Photochemistry is important in every case.
Tuesday, December 22, 2009 13 Neptune’s Stratosphere mid-IR
Gemini/Michelle at 11.7 µm Ethane Emission from the stratosphere
All 3 images taken within a few minutes on 5 July 2005 Gemini/Michelle at 7.7 µm Methane Emission from the stratosphere
Keck/NIRC2+AO at 1.6 µm Sunlight Scattering from tropospheric Clouds
Hammel et al. (2007) Can we achieve a better understanding of the energetics of giant planet stratospheres?
Tuesday, December 22, 2009 14 Fortney et al. (2008)
Tuesday, December 22, 2009 15 Tuesday, December 22, 2009 16 Strong downdrafts at Jovian hotspots (Showman & Dowling 2000)
Hot Jupiter GCM (Showman et al. 2008)
Tuesday, December 22, 2009 17 Core Masses?
Fortney et al. (2009) oklo.org Tuesday, December 22, 2009 18 Ice Giant Magnetospheres
Earth
Jupiter Saturn
Uranus Neptune
Stably- Solid stratified Stanley & Bloxham (2006)
Tuesday, December 22, 2009 19 Ring-Plane Crossing of Uranus
2001 2002 2003 2004 2005 2006 2007 Keck images of Uranus in 2007 show a rare view of the unlit side of the rings
Such ring-plane crossings occur every 42 years; the last—in 1965—was prior to the rings' discovery in 1977!
Tuesday, December 22, 2009 20 New Rings of Uranus
Two new rings discovered with HST and Voyager by Showalter and Lissauer (2005) Keck images (de Pater et al. 2006) reveal ringsʼ colors and striking similarity with Saturnʼs rings Photo-Illustration compares the Saturn and Uranus ring systems
Red = Saturn G ring, Uranus R2 Blue = Saturn E ring, Uranus R1
Tuesday, December 22, 2009 21 Nearly all aspects of the Neptune system detectable from Earth have changed significantly since Voyager fly-by in 1989
• The ring system has changed – Arcs evolved within <8 yrs
The dynamic neptunian ring arcs: evidence for a gradual disappearance of Liberté and resonant jump of courage
de Pater, Imke; Gibbard, Seran G.; Chiang, Eugene; Hammel, Heidi B.; Macintosh, Bruce; Marchis, Franck; Martin, Shuleen C.; Roe, Henry G.; Showalter, Mark
Icarus, Volume 174, Issue 1, p. 263-272
Both the location and intensity of all arcs changed drastically relative to trailing arc Fraternité... Our data suggest that all arcs may have decayed over the last decade, while Liberté, in 2003, may be on the verge of disappearing completely. The observed changes in the relative intensities and locations of all arcs further indicate that material is migrating between resonance sites; leading arc Courage, for example, has jumped ˜8° (one full corotation potential maximum). Overall, our observations reveal a system that is surprisingly dynamic, and no comprehensive theory exists as of yet that can explain all the observed intricacies.
Tuesday, December 22, 2009 22 Kalas et al. (2008)
Tuesday, December 22, 2009 23 Decadal Process
Tuesday, December 22, 2009 24 White Papers • ~ 100 white papers submitted • mission concepts • technologies • existing facilities • laboratory and theory work • other topics • All read and discussed and important basis for ongoing activities
Tuesday, December 22, 2009 25 Selected Three Targets for RMA Studies
• Neptune/Triton/KBO • Uranus • Saturn
Tuesday, December 22, 2009 26 Mission Studies • Neptune-Triton-KBO flyby or Neptune orbiter • entry probe • free flying nanosats • meetings complete, report in preparation • Saturn entry probe(s) - ongoing • Uranus orbiter - ongoing • May choose some for point designs
Tuesday, December 22, 2009 27 Technology Issues
• Power • Plutonium supply • ASRG lifetime • Communications (DSN) • Aerocapture/Aerobraking • Entry probes, daughter probes • Nanosats • Instrumentation
Tuesday, December 22, 2009 28 GPP Outreach Activities
Date Meeting Location Plan
13 July 2009 OPAG Columbia, MD Attend/Follow-up
27-31 July 2009 Mag. Outer Planets Cologne Attend/Follow-up
Aug-Sep 2009 - - GPP Web survey
Aug-Sep 2009 - - GPP Phone campaign
24-26 Aug 2009 PANEL MEETING Washington, DC -
4-9 Oct 2009 DPS Puerto Rico Workshop
26-28 Oct 2009 PANEL MEETING Irvine, CA -
14-18 Dec 2009 AGU San Francisco Attend/Follow-up
1-5 March 2010 LPSC Houston Attend/Follow-up
4-6 May 2010 PANEL MEETING Boston, MA -
Tuesday, December 22, 2009 29 Your Input
Tuesday, December 22, 2009 30