SOFIA - Planetary System “Awesome” Science

Panel membershipApproximate panel schedule

Planetary science categories

Some science examples- solar system- planetary system formation- exoplanets

Science Vision off-site meeting, June 6, 2008

OUTLINE:

Planetary System Science Panel

Jeff Cuzzi (lead): planetary rings and moons, planetary formation

Dana Backman (deputy): planet and star formation [provide main panel connection to the project; answer “feasibility” questions]

Athena Coustenis: Titan

Dale Cruikshank and Josh Emery: primitive bodies: asteroids, Centaurs, Trans-Neptunian Objects, Kuiper Belt Objects, etc.

Bob Haberle, Jeff Hollingsworth: Terrestrial planet atmospheres

Mark Marley: exoplanets

Mike Mumma: comets

Glenn Orton: gas giant planets

(Joan Najita: circumstellar disks; Ted Dunham: internal reviewer)

Science Vision - Planetary Science Panel

Review of past work

Augmentation of past work

Identification of “awesome” science subset

Writeup

General Plan:

Planetary System Science Schedule

May 20: kickoff telecon

June: get updated write-up from AAS group (Black) get final Vision 2020 document (Young) get updated DRM cases (several)

July: several more telecons and off-line coordination

August: Bulk of writing

August 29: First version for internal review Goal: 10 pages including figures; 3-5 major topics

October 1: Receive final guidance from reviewers and SOFIA project

October 8: Final draft

October 8-23: zone of avoidance (DPS, Cassini PSG, other travel)(except, possible presentation to SOFIA workshop at the DPS)

October 24: presentation for Blue Ribbon Panel

SOFIA - Special Planetary Capabilities

Can image the Jovian planets and their nearby moons- @ wavelengths of their peak continuum emission- @ wavelengths of organic molecular lines

Can point at r < 1 AU- Venus and Mercury- Comets most active

Can go anywhere on Earth to reach occultation shadowsof solar system objects

SOFIA - Planetary System “Awesome” Science

Gas & Ice giant planets and moons:* water abundance, H/He ratio, D/H ratio, isotopic abundances[how did the solar system form? what was the “big bang” density?]* thermal properties (spatial and temporal variations, tidal heating)[how did the giant planets form? which moons may have oceans?]

Primitive Bodies: comets, centaurs, TNOs, asteroidsmaybe only the brightest of the TNOs directly accessibleothers: diversity requires population studies

* occultations (sizes & densities, atmospheres, companions)[how did the solar system form? did the giant planets migrate?]* spectroscopy (water, volatiles, organics, minerals, crystallinity, D/H)[how did the solar system form? how abundant are biology precursors?]

SOFIA - Planetary System “Awesome” Science, cont’

Planet Formation: chemistry in Terrestrial zones[how do our solar system’s properties, especially astrobiology

aspects, fit in relative to planetary systems forming now?]

Exoplanets: transit detection(?) and spectroscopy; HST-like sensitivity[significance of “hot Jupiters” in relation to uniqueness, or not, of our solar system’s architecture]

SOFIA - Planetary System “Awesome” Science, cont’

Inner solar system:* Mercury sodium[how did Mercury form? properties don’t fit condensation sequence…]* Venus’s deuterium abundance, evidence for a vanished ocean[Earth’s twin gone bad?]

Titan atmosphere composition (and dynamics?)[big organics factory; low-temperature analog to pre-life Earth]

Mars atmospheric evolution, dynamics: * water cycle …?* biogenic methane ? (large-scale spatial variations)[does life exist on Mars, or did life exist there once?]

Solar System Objectives (from 2006 HQ Roadmap)

• How did the Sun’s family of planets & minor bodies originate?

• How did the Solar System evolve to its current diverse state?

• What SS characteristics led to the origin of life?

• How did life begin & evolve on Earth; has it evolved elsewhere in the SS?

• What hazards & resources of SS will affect extension of human presence in space?

Augmented objectives given breakdown of other groups

• How do planetary systems form in their parent protoplanetary disks?• How do extrasolar planetary systems evolve to their current diverse state?• What planetary system characteristics may lead to the origin of life?• What do brown dwarfs tell us about the planet formation process?

Assertions

• “Awesome” Science will be done on important, far-reaching clusters of problems where SOFIA’s combination of sensitivity, spectral coverage, spectral resolution, long program duration, and spatial mobility and flexibility are critical

• SOFIA will not be competitive in areas where photometric stability, or high sensitivity and low noise, are critical.

• If we were the SOFIA TAC, what are the N (10?) most important scientific problems we would assign all its (solar system and exoplanet) time to? These will probably be object-centered but should be clearly related to high-level science objectives.

• “Other good science” can be noted, i.e. in an Appendix. • Avoid “preaching to the choir” tone; document will be read by non-

advocates

Issues• 1st (1-30) and 2nd (40-600) generation instruments; how real is, and when do

we get the 2nd generation? Could “Awesome” Science rely partly on gen-2?

FayaliteFe2SiO4

ForsteriteMg2SiO4

Woodward; from Koike et al 2003

mineralogy

Ortho-para ratio gives formation temp

Comets - 2020 package by Woodward

Access to water vapor spectral featuresMobility allows observation from both hemispheresLow elevation range allows low solar elongationLarge aperture allows observation of distant cometsSpatial resolutionProximity < 82deg to sun

Diversity of primitive bodies

Lisse et al Spitzer Warm era

Spectroscopy (composition)

Occultations (size, density, atmosphere)

Gas and Ice giants

GREAT capabilityTemporal variabilityIsotope abundances

Occultations at many latitudes/longitudes/times?

Mid- and Far-IR spectral line sounding will determine H/He ratio (i.e. He mixing ratio) and vertical temperature profiles

D/H ratio can be determined from FIR rotational transitions of HD

Time Variations?

Saturn’s moon Enceladus

Jupiter’s moon Io

Mars (and Titan?) meteorology

Mars: zonal winds from 162 CO2 line Doppler

• German interest in far-IR heterodyne spectroscopy for planetary science.

• Atmospheric sounding by line profile inversion.

• Line profiles depend on temperature, pressure, and mixing ratio.

• Vertical temperature and mixing ratio profiles can be retrieved from high S/N line profiles.

Wavelength??

Temp Profile Retrieval

Water VaporProfile

Retrieval

Mars (and Titan?) meteorology

Wavelength??

Titan model with and without propane

HD 209458 artist’s concept (left) and HST STIS data (below)

Exoplanets

FLITECAM tuneable narrowband filters

Transits of a planet and itsrarefied exosphere:

Atmospheric composition and structureAtmospheric chemistry

HIPO

HD209458b

Na?

Tinetti et al 2007

With clouds

Without clouds

Burroughs

Exoplanet size, density, structure, atmospheric structure and composition

CH4

(?)

Protoplanetary Disks - gas

12 µm

17 µm

28µm

Carr, Najita, Salyk et al use narrow lines in several different spectral regions to characterize nebula opacity sourcesand the redistribution of solids. Future work may include isotopic abundances. Sensitivity maybe an issue. Possible second generation instrument?

EXES on SOFIA can resolve line profiles of emission arising from warmer inner (<~10AU) parts of the disk, constraining the gas mass and morphology. Some lines expected are H2 (28 µm), S I (25 µm), and Fe II (26 µm). Also H2O, CH4, and CO should be detectable, and possibly HCN and C2H2. (and SiO?)

Protoplanetary Disks - solids

Crystallinity? Fe/Mg ratio? Transport?