Universities Space Research Association Communications Integrated Systems NAPA Meeting 8-14-06 Page 1 A sampler of planetary science applications of SOFIA

Universities Space Research Association

NAPA Meeting 8-14-06 Page 1

CommunicationsIntegrated Systems

• A sampler of planetary science applications of SOFIA

Mineralogy of Mercury

Martian wind and water

Spectroscopy of the giant planets

Occultation astronomy

Comets

Ephemeral events





Radar image of the hemisphere not imaged byMariner 10 shows two areas

of enhanced roughness.

Groundbased spectroscopy shows enhanced sodium emission, likely

connected to these regions.

What underlying mineralogy is the source of the atmospheric sodium?





The strength and exact location of a spectral feature near 6 microns can be used to distinguish among several candidate surface mineral assemblages. This wavelength is not accessible to ground-based observers but is observable with SOFIA.

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5 6 7 8 9 10 11 12Wavelength (microns)

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KAO, 7/6/95

KAO, 5/8/95

Basalt (H1)

Anorthosite (H2)

Nepheline alkali syenite (H2)




Martian Wind and Water• 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.

This is a promising approach for locating subsurface reservoirs of water on Mars.




Martian Atmospheric Structure

Temperature Profile

Retrieval

Water VaporMixing Ratio

Profile Retrieval




Zonal Wind Measurement

Simulation of a zonal wind measurement using the doppler shift of the 162 micron Martian CO line.




Spectroscopy of the Giant Planets

Water on Jupiter and Saturn

• Galileo probe entered in an NEB hot spot, also the easiest (brightest) locations for remote sensing

• Hot spots are very dry, but can’t be representativeKAO 5-micron spectroscopyGalileo probe in-situ measurement

• Water first detected on Saturn by ISO. Need higher spatial resolution

• No water measurement possible with Cassini

•SOFIA needed to determine water abundance in other regions.Zones have extinction from clouds => need higher sensitivityNeed spatial resolution to separate zones from beltsAirborne platform to minimize interference from telluric water




Spectroscopy of the Giant Planets

Uranus and Neptune

• More distant and colder than Jupiter and Saturn=> Need SOFIA’s high sensitivity

• Interesting comparative targets, like Earth and VenusSimilar sizes Neptune has an internal heat sourceDifferent amounts of atmospheric activity

• 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




• Spatial resolution is limited by diffraction, (~ 1-2 km), the angular diameter of the occulted star, and the lightcurve S/N ratio

Examples of airborne occultation results:• Discovery of the central flash phenomenon• Discovery of the Uranian rings• Discovery of Pluto’s unusual atmospheric structure

What Do We Learn From Stellar Occultation Observations?

Intensity

Time

The mechanisms dimming the star are:• Refraction in an atmosphere• Extinction by particles, aerosols, or the solid body of the occulting object

• Refractive lightcurves can be inverted to provide temperature profiles in a region between UVS and radio occultations. KAO (1988) Pluto occultation lightcurve




Occultation Work with SOFIA

Technical:

• Much larger aperture, more sensitive and faster instruments• Simultaneous optical/IR observing• Lower elevation limit - fewer missed opportunities

Scientific:

Triton and Pluto - comparative planetology• Seasonal change in atmospheric density, already detected on Triton• Is the Pluto occultation lightcurve due to an inversion or to extinction?

Kuiper Belt Objects• What is a typical KBO albedo?• Are there different types of KBO surfaces?• These are very small and distant objects. Prediction is challenging and mobility is critical.




Comets

• Comets are the closest we can get to primordial material

• Water is the driving force in comets

• Many organic materials are present with spectral features at wavelengths that are inaccessible to ground-based telescopes

SOFIA will be uniquely able to contribute to comet science:• Access to water vapor spectral features• Mobility allows observation from both hemispheres• Low elevation range allows observation at low solar elongation• Large aperture allows observation of distant comets




Ephemeral Events

The impact of comet Shoemaker-Levy 9 on Jupiter:The ultimate ephemeral event.

The KAO program was able to:• Hold a peer review• Support three investigations• Deploy to Australia to maximize productivity• Carry out an ambitious flight schedule - 7 flights in 9 days with 2 instrument changes




The 1994 “Comet Crash”

Major Airborne Contributions:

• Detection of hot water vapor and no cold water vapor => cometary nucleus is the source, high altitude explosion

• Intense emission from methane provided an independent temperature measurement.

• No detectable FIR water emission after the impacts also supports high altitude terminal disruption.



CommunicationsIntegrated SystemsScience

A few SOFIA Science Examples:

Stellar Occultations by Solar System Objects:Shadows of SSOs cast by stars may appear anywhere on earth - Measureable sizes > ~ 200 km - Ground speed up to ~ 30 km/s SOFIA can be there, free from clouds and scintillation noise - High-speed photometry achieves ~ few km resolution - Numerous useful occultation events possible each year

Simultaneous HIPO (visible) and FLITECAM (NIR) data will - Probe atmospheres & rings (Rings of Uranus were discovered from KAO) - Establish sizes of ~ 30 KBOs (eg Sedna), constraining geometric albedo - Confront details of solar system formation models (debris disks)

Extrasolar Planet Transits: Possible with S/N comparable to HST - Estimate planet sizes - With Doppler velocity observations, estimate planet densities

Dunham




SOFIA + ALMA Studies of Protoplanetary Disks

ALMA will image the millimeter dust continuum and CO emission, resolving scales ~10 AU, to examine morphology, and to estimate dust and gas content; gas kinematics will constrain the stellar mass.

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.

Theoretical H2 line profiles from a disk with and without gap at 3 AU.

12 µm

17 µm

28µm

Combination will challenge disk structure and chemistry models

Science

Lacy




Habitats for Life: SOFIA will reveal the cycle of organic molecules

SOFIA can tell us:

what molecules are forming in the atmospheres of Red Giant Stars…

…about the processing that takes place in

the Interstellar Medium

…and what organic constituents are incorporated into protoplanetary disks.

Plus: SOFIA observation of comets can help to provide an inventory of the organic matter in the primitive Solar Nebula.

Science




Transits of Extrasolar planets• SOFIA will fly above the scintillating components of the

atmosphere with optical sensitivity comparable to HST to observe extrasolar planetary transits.

• HIPO will be able to detect weak transit signals with high signal-to-noise, conclusively determining the status of candidate extrasolar planets discovered by transit surveys. SOFIA’S long life will be a boon to this program.

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

Science




Stellar Occultations of Solar System objectsSimultaneous HIPO (visible) and FLITECAM (NIR) data will

– Probe atmospheres & rings (Rings of Uranus were discovered from KAO)

– Establish sizes of satellites & KBOs (eg SEDNA) at ~ few km resolution Confront details of solar system formation models

Science

Numerous occultation events per year are expected to be possible with SOFIA!

The Outer Solar System










ISO Titan spectraand Roe et al. (2003) TEXES spectra




Titan model with and without propane




Probing Kuiper Belt Objects

Spitzer can detect or set limits on KBO fluxes to determine sizes / albedosSOFIA will see Stellar Occultations of Solar System objects

– Probes atmospheres, satellites, & rings uniquely between rare mission fly-bys– Uniquely probes the sizes of objects such as Sedna and KBOs; visible & near-IR

data simultaneously with HIPO & FLITECAM

Expecting approximately three occultation events per year with SOFIA




SOFIA in comparison with other observatories

• Comparison of capabilities – Large NIR ground-based Observatories; “Gemini”– JWST

– Spitzer– Herschel– Large ground-based Sub-MM Observatories; “JCMT”

– Sub-MM and MM Interferometers; “ALMA”

• Comparison of timelines

• Objective: To show how SOFIA fits into the “Big Picture” of Far-IR Universe Exploration




Examples of Complementary Studies of Protoplanetary Disks Around Pre-MS Stars• ALMA:

• Image the MM dust continuum and molecular emission • Resolving scales ~1 - 10 AU• Morphology; estimate dust and gas content; gas kinematics

• Gemini-like Ground-based observatories: • Detect hot dust continuum emission (from <~few AU)• Resolve fluorescent spectral line/feature emission caused by exposure to UV radiation

• SOFIA (emission from ~ 0.3 - 30 AU i.e., where terrestrial planets form): • Resolve line profiles of emission arising from warmer inner (<~10AU) parts of the disk

•H2 (28 µm), S I (25 µm), and Fe II (26 µm), H2O, CH4, and CO should be detectable, and possibly HCN and C2H2

• In addition, resolve line profiles of gas tracers [O I] and [C II] in emission throughout the disk, and accretion shock OH lines in forming disks • Constraining the gas mass; thermal balance; vertical structure; chemistry; disk formation




Atmospheric Transmission andObservatory Wavelength Ranges

Infrared/Sub-MM Observatories

SOFIA Herschel

Hubble

JWSTSAFIR

Ground-Bound“Gemini” “JCMT & ALMA”

Spitzer




SOFIA compared with other Observatories

SOFIA and Herschel will provide images of the Far-IR Universe with at least three times the spatial resolution ever achieved before. 1

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Angular Resolution

SOFIA 50% EL Diam (arcsec)

SOFIA 50% EL Diam (arcsec)

KAO 50% EL Diam (arcsec)

KAO 50% EL Diam (arcsec)

SIRTF 50% EL Diam (arcsec)

SIRTF 50% EL Diam (arcsec)

ISO 50% EL Diam (arcsec)

IRAS A 50% EL Diam (arcsec)

IRAS B 50% EL Diam (arcsec)

IRAS C 50% EL Diam (arcsec)

IRAS D 50% EL Diam (arcsec)

~ 50% Enclosed LightDiameter (arcsec)

Wavelength (µm)

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SpitzerSOFIA

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~0.01”

ALMA




SOFIA compared with other Observatories

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Photometric Sensitivity SOFIA 1 sigma FD (mJy)KAO 1 sigma FD (mJy)SIRTF ASIRTF BSIRTF CSIRTF DSIRTF ESIRTF FSIRTF GISO_B 1 sigma FD (mJy)ISO_C 1 sigma FD (mJy)ISO_D 1 sigma FD (mJy)ISO_E 1 sigma FD (mJy)ISO_F 1 sigma FD (mJy)ISO_G 1 sigma FD (mJy)ISO_H 1 sigma FD (mJy)IRAS A 1 sigma FD (mJy)IRAS B 1 sigma FD (mJy)IRAS C 1 sigma FD (mJy)IRAS D 1 sigma FD (mJy)

Photometric Sensitivity1 Sigma, 1 hr, Flux Density (mJy)

Wavelength (µm)

SOFIA

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Herschel

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Spitzer and Herschel will provide best sensitivity in the Far-IR so far achieved

SOFIA will provide the best spectral coverage and spectral resolutions




SOFIA’s first generation of Science Instruments….

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First Generation SOFIA Instruments




More coverage than any other IR/sub-mm space mission planned or currently operating.

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SOFIASOFIA - 2006 to 2009 (1st Generation)- 2006 to 2009 (1st Generation)

Spitzer Spitzer - 2003 to 2008- 2003 to 2008

Herschel Herschel - 2007 to 2010- 2007 to 2010

JWST - JWST - >2011>2011

HerschelHerschel

Comparison of spectroscopic capabilities of SOFIA 1st Generation instruments to other observatories

HerschelHerschelFIFI LS

CASIMIR

JWSTJWST

HerschelHerschel




More coverage than any other IR/sub-mm observatory planned or currently operating.

Ground-Based Observatories

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SOFIASOFIA - 2006 to 2009 (1st Generation)- 2006 to 2009 (1st Generation)

Spitzer Spitzer - 2003 to 2008- 2003 to 2008

Astro_F Astro_F - 2005 to 2007- 2005 to 2007

Herschel Herschel - 2007 to 2010- 2007 to 2010

JWST - JWST - >2011>2011

HerschelHerschel

HerschelHerschel

Comparison of spectroscopic capabilities of SOFIA 1st Generation instruments to other observatories

HerschelHerschelFIFI LS

CASIMIR

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Grey bands

= ground-

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Every four/five years SOFIA re-invents itself….

New SOFIA instruments will:• Extend spectral resolution coverage• Add polarimeters• Extend detector array sizes• Improve data acquisition techniques• Increase field of view

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SOFIA SOFIA - beyond - beyond first-generationfirst-generation




…and will likely be the only window to the luminous Far-IR Universe in the decade of 2010

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Spitzer

HerschelSOFIA

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Frequency (THz)

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IR - Far IR - Sub-mm Observatories

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Ground-based Observatories

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IR - Far IR - Sub-mm Missions

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Airborne observatories provide temporal continuity and wide spectral coverage, complementing other facilities.

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Rationale

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Infrared Space Observatories

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SOFIA provides temporal continuity and wide spectral coverage, complementing other infrared observatories.




SOFIA and Spitzer

• SOFIA will become operational near the time that Spitzer runs out of cryogens. The science impact of not being contemporary is small: Spitzer is a high sensitivity imaging and low resolution spectroscopy mission. SOFIA is a high spectral and high angular resolution mission

• As it now stands, the two observatories are very complementary and when Spitzer runs out of cryogens in early FY09, SOFIA will be the only observatory working in the 25 to 60 micron region for over 10 years: Comets, Supernovae, Variable AGN, other discoveries.




SOFIA / Spitzer Capabilities Comments

• Opportunity for significant operations overlap (2006 - 2008)– Important to have ~3yr overlap for coordinating Spitzer / SOFIA followups

– Allows simultaneous Spitzer / SOFIA observations of time variable phenomena (e.g. protostellar accretion over = 3 - 300 m)

• Spitzer has tremendous sensitivity, especially at shorter wavelengths; sensitivity matched with SOFIA at ~160 m. Spitzer + SOFIA span an incredible dynamic range with good overlap!

• SOFIA has 3x diffraction-limited spatial resolution– SOFIA @ =24 m (FORCAST / EXES) will have same angular resolution as Spitzer IRAC / IRS

@ =8m

– SOFIA @ =52 & 88 m (HAWC; FIFI-LS) will have similar or better angular resolution than Spitzer (MIPS; IRS) @ =24m

• SOFIA has higher spectral resolution, different coverage– FLITECAM @ R=2000 (=1 – 5 m); EXES @ R=105 (=5 – 28 m); FIFI-LS @ R=2000 (= 40-

210m)

– SOFIA has heterodyne spectroscopy @ >110 m (1st light)

– Spitzer IRS has R=70 over = 5-10m and up to R=600 over = 10-38m




Some Synergistic Science Examples

• Bright debris disks: Understanding the archetypes

• Tracing planet formation clues

• Organic matter in the ISM

• Resolving star formation

• Leveraging the Legacies

• Probing KBOs




Evolution of proto-planetary dust & gas disks into planetary systems:

SOFIA can resolve the nearby debris disks and obtain dust SED-> Giving disk dust properties, size and mass, as well as disk structure

-> Giving evidence for planets

-> Complementing to SED disk gap results that Spitzer will find for MANY disk systems… (next page)

SOFIA EXES can detect disk clearing by planets forming in circumstellar disks using high-resolution spectroscopy of H2,

H2O, & CH4 lines with ~3 km/s resolution




Spitzer Infers Circumstellar Disk Gaps




Spectroscopic Dissection

• Spitzer will find ices, hydrocarbons, and other organic matter in many objects

• SOFIA has the spectral resolution needed to identify compounds precisely to allow detailed physical and chemical analysis

Boogert (1999) ISO SWS observations of CO fundamental in YSO Elias 29. Solid CO is detected at R=400 and 2000, but gas-phase CO is detected at R=2000 only.




Leveraging the Spitzer Legacies

• High spatial resolution FORCAST, FIFI-LS, & HAWC observations of SINGS galaxies resolve embedded star formation.– circumnuclear and (partial) disk mapping of ~10 sources (1-2 flights) with FIFI-

LS

• Resolve confused or saturated galactic plane regions in GLIMPSE survey

• High spatial & spectral (accretion /jet diagnostics) observations of C2D protostars (EXES, FORCAST grism)

• High resolution maps of bright disks and spectra (e.g. H2 gas search with EXES) of FEPS post-planetary disks.




SINGS: Spitzer Nearby Galaxies Survey

• Basic idea: Study star formation and galaxy evolution by observing mid-to-far-IR emission (IRAC & MIPS)

• Observe 75 nearby galaxies with IRAC, MIPS, and IRS in nearly every instrument mode! (3.6 – 160 m imaging; 5 – 37 m spectroscopy @ high & low resolution).

MIPS (red) & IRAC MIPS SED + IRS low IRS low & hi pointings




SOFIA Science Capability Summary

• Exciting unique science to be done with SOFIA– Occultations, extrasolar planets, molecular & atomic gas,

galactic center

• SOFIA’s compelling far-IR and sub-mm science will only get better with new detectors– Better arrays, heterodyne detectors, higher , bigger

bolometers, etc.

• SOFIA & Spitzer are a synergistic combination - the whole of their data will have much more value than either observatory alone: – Spatial resolution, dynamic range, spectral coverage &

resolution




SOFIA and Herschel

• Herschel and SOFIA will now start at about the same time• Joint calibration work is on going• For the years of overlap, SOFIA will be only program

– with 25 to 60 micron capability– with high resolution spectroscopy in the 60 to 150 micron region

• When cryogens run out in Herschel in ~2011 SOFIA will be only NASA mission in 25 to 600 micron region for many years– Important follow-up– Advanced instrumentation will give unique capabilities to SOFIA:

Polarization, Heterodyne Arrays, Heterodyne Spectroscopy at 28 microns (ground state of molecular hydrogen), and other interesting astrophysics lines

• Both missions are critically important and complementary




SOFIA and JWST

• SOFIA is very complementary to JWST

• Before JWST is deployed and after Spitzer cryogens run out , SOFIA is only mission with 5 to 8 micron capabilities– important organic signatures

• After JWST is launched SOFIA is the only mission to give complementary observation beyond 28 microns and high resolution spectroscopy in 5 to 28 micron region




SOFIA will make major contributions to our understanding of…..

• Structure and evolution of galaxies and their central black holes• Lifecycle of stars in the Milky Way and other galaxies

– First and last stages of stellar evolution• Molecular clouds as cradles for star and planet formation• Emergence of stellar and planetary systems• Habitats for life in the Milky Way

– Organic chemistry in the ISM• Evolution of proto-planetary dust and gas disks into planetary systems

– Evidence of planets in disks around young stars• Extrasolar planets (transits)• Atmospheres & multiplicity of objects in outer solar system

– Evolution of our system for comparison with extrasolar systems

…. topics on the Origins 2003 Roadmap (with some SEU and SSE relevance)




In summary ….• SOFIA has unique spectral and temporal coverage

– High-resolution spectroscopy, unique at 28 < < 150 m• Exploring the physics/chemistry behind phenomena

– (/10 m) arc-sec image quality, unique for 30 < < ~60 m– Unique long operating lifetime

• Accretion phenomena; Planetary disks; Transits; Supernovae

• SOFIA will increase its unique complement of capabilities in the future– E.g., Polarimetry

• Determine the relevance of magnetic fields in– Star Formation; Protoplanetary Disk formation; Galactic processes

• SOFIA will be a test-bed of technologies for future Far-IR missions– Large far-IR detector arrays

• increased mapping capabilities

• SOFIA is a hands-on Far-IR observatory– Will train future mission scientists and instrumentalists




Science Summary

• The science vision for SOFIA is:– Studying the origin of stars and planetary systems– Studying the planetary bodies that make up our Solar System– Studying the life-cyle of dust and gas in galaxies– Studying the composition of the molecular universe– Studying the role of star formation and black hole activity in the energetics of

luminous galaxies

• SOFIA has a unique suite of instruments that cover a wide range of wavelengths at a wide range of spectral resolution. Most have upgraded their detectors and science.

• SOFIA will be continuously and inexpensively upgraded with new instrumentation and will serve as an important technology development platform for future space missions and will allow new and important science, such a full mapping of molecular hydrogen and unique magnetic field studies.

• SOFIA is a highly visible icon for education and public outreach and will immerse educators in the scientific process.

Documents

Universities Space Research Association Communications Integrated Systems NAPA Meeting 8-14-06 Page 1 A sampler of planetary science applications of SOFIA