Mixing Ratio Profile Retrieval. Universities Space Researc

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• 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

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Mineralogy of Mercury
Radar image of the hemisphere not imaged
by Mariner 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?
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Mineralogy of Mercury
1.2
Basalt (H1)
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.
1.1
Anorthosite (H2)
1.0
Nepheline alkali syenite (H2)
0.9
Normalized Spectral Emissivity
0.8
KAO, 5/8/95
0.7
KAO, 7/6/95
0.6
5 6 7 8 9
10 11 12 Wavelength
(microns)
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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.
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Martian Atmospheric Structure
Temperature Profile Retrieval
Water Vapor Mixing Ratio Profile Retrieval
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Zonal Wind Measurement
Simulation of a zonal wind measurement using the
doppler shift of the 162 micron Martian CO line.
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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 cant be
  representative
• KAO 5-micron spectroscopy
• Galileo 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 gt need higher
  sensitivity
• Need spatial resolution to separate zones from
  belts
• Airborne platform to minimize interference from
  telluric water

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Spectroscopy of the Giant Planets

• Uranus and Neptune
• More distant and colder than Jupiter and Saturn
• gt Need SOFIAs high sensitivity
• Interesting comparative targets, like Earth and
  Venus
• Similar sizes
• Neptune has an internal heat source
• Different 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

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What Do We Learn From Stellar Occultation
Observations?

• 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

• 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 Plutos unusual atmospheric
  structure

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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.

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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

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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

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The 1994 Comet Crash

• Major Airborne Contributions
• Detection of hot water vapor and no
• cold water vapor gt 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.

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A few SOFIA Science Examples
Stellar Occultations by Solar System
Objects Shadows of SSOs cast by stars may appear
anywhere on earth
- Measureable sizes gt 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
Science
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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 (lt10AU) 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.
12 µm
17 µm
28µm
Combination will challenge disk structure and
chemistry models
Theoretical H2 line profiles from a disk with and
without gap at 3 AU.
Lacy
Science
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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
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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. SOFIAS
  long life will be a boon to this program.

Science
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• Stellar Occultations of Solar System objects
• Simultaneous 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

The Outer Solar System
Numerous occultation events per year are expected
to be possible with SOFIA!
Science
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ISO Titan spectraand Roe et al. (2003) TEXES
spectra
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Titan model with and without propane
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Probing Kuiper Belt Objects

• Spitzer can detect or set limits on KBO fluxes to
  determine sizes / albedos
• SOFIA 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
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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

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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 ltfew
  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 (lt10AU) 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

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Atmospheric Transmission andObservatory
Wavelength Ranges
Gemini
JCMT ALMA
Ground-Bound
Spitzer
SOFIA
Herschel
JWST
SAFIR
Infrared/Sub-MM Observatories
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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.
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SOFIA compared with other Observatories
Spitzer and Herschel will provide best
sensitivity in the Far-IR so far achieved
SOFIA will provide the best spectral coverage and
spectral resolutions
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SOFIAs first generation of Science Instruments.
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More coverage than any other IR/sub-mm space
mission planned or currently operating.
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More coverage than any other IR/sub-mm
observatory planned or currently operating.
Grey bands ground- bound
Ground-Based Observatories
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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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and will likely be the only window to the
luminous Far-IR Universe in the decade of 2010
2000
2010
2020
Spitzer
SAFIR
Herschel
SOFIA
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IR - Far IR - Sub-mm Observatories
0.3
1000
SAFIR
Frequency (THz)
Herschel
3
100
SOFIA

JWST
Wavelength (µm)
30
SPITZER
10
1
2000
2005
2010
2015
2020
SOFIA
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IR - Far IR - Sub-mm Missions
ODIN
0.3
1000
Planck
KAO
SWAS
SAFIR
Frequency (THz)
Herschel
Herschel
3
100

ASTRO-F
JWST
Wavelength (µm)
Spitzer
30
10
COBE
IRAS
SOFIA
ISO
WISE
1
1980
1990
2000
2010
2020
Year
Airborne observatories provide temporal
continuity and wide spectral coverage,
complementing other facilities.
Rationale
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Infrared Space Observatories
0.3
1000
?
SAFIR
Frequency (THz)
Herschel
SOFIA
3
100

JWST
SPITZER
Wavelength (µm)
30
10
1
2005
2010
2015
2020
2025
SOFIA provides temporal continuity and wide
spectral coverage, complementing other infrared
observatories.
Ground-based Observatories
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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.

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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 l 3 - 300 mm)
• Spitzer has tremendous sensitivity, especially at
  shorter wavelengths sensitivity matched with
  SOFIA at l 160 mm. Spitzer SOFIA span an
  incredible dynamic range with good overlap!
• SOFIA has 3x diffraction-limited spatial
  resolution
• SOFIA _at_ l 24 mm (FORCAST / EXES) will have same
  angular resolution as Spitzer IRAC / IRS _at_ l8mm
• SOFIA _at_ l 52 88 mm (HAWC FIFI-LS) will have
  similar or better angular resolution than Spitzer
  (MIPS IRS) _at_ l24mm
• SOFIA has higher spectral resolution, different l
  coverage
• FLITECAM _at_ R2000 (l1 5 mm) EXES _at_ R105 (l5
  28 mm) FIFI-LS _at_ R2000 (l 40-210mm)
• SOFIA has heterodyne spectroscopy _at_ l gt110 mm
  (1st light)
• Spitzer IRS has R70 over l 5-10mm and up to
  R600 over l 10-38mm

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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

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Evolution of proto-planetary dust gas disks
into planetary systems

• 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

SOFIA can resolve the nearby debris disks and
obtain dust SED -gt Giving disk dust properties,
size and mass, as well as disk structure -gt
Giving evidence for planets -gt Complementing to
SED disk gap results that Spitzer will find for
MANY disk systems (next page)
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Spitzer Infers Circumstellar Disk Gaps
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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 R400 and 2000, but gas-phase CO is detected
at R2000 only.
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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.

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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
  mm imaging 5 37 mm spectroscopy _at_ high low
  resolution).

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SOFIA Science Capability Summary

• Exciting unique science to be done with SOFIA
• Occultations, extrasolar planets, molecular
  atomic gas, galactic center
• SOFIAs 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

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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

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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

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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)

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In summary .

• SOFIA has unique spectral and temporal coverage
• High-resolution spectroscopy, unique at 28 lt l lt
  150 mm
• Exploring the physics/chemistry behind phenomena
• (l/10 mm) arc-sec image quality, unique for 30 lt
  l lt 60 mm
• 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

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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.