Transcript borucki

KEPLER
William Borucki, PI
Solar System Exploration
Subcommittee
Sante Fe, New Mexico
February 14-15, 2005
Science Team
William J. Borucki, PI, and David Koch, Deputy PI
Stellar Occultations & High-Precision
CCD Photometry
•Timothy Brown, HAO, UCAR
•Edward Dunham, Lowell Obs.
•John Geary, SAO
•Ronald Gilliland, STScI
•Steve Howell, U. Ariz
•Jon M. Jenkins, SETI Institute
Doppler Velocity Planet Searches
•William Cochran, UTexas
•David Latham, CfA, SAO
•Geoff Marcy, U. Cal., Berkeley
Stellar Variability
•Gibor Basri, U. Cal., Berkeley
•Andrea Dupree, CfA, SAO
•Dmiter Sasselov, CfA, SAO
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Theoretical Studies
•Alan Boss, Carneige Institute Wash.
•Jack Lissauer, NASA Ames
Mission Operations
•Donald Brownlee, U. of Washington
•Yoji Kondo, NASA GSGC
General Overview
•John Caldwell, York U.
•David Morrison, NASA Ames
•Tobias Owen, Hawaii
•Harold Reitsema, Ball Aerospace Co.
•Jill Tarter, SETI Institute
Education and Public Outreach
•Edna DeVore, SETI Institute
•Alan Gould, Lawrence Hall of Science
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KEY QUESTIONS:
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Are terrestrial planets common or rare?
How many are in the habitable zone?
What are their sizes & distances?
Dependence on stellar properties
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Scientific Goals
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Determine the frequency of terrestrial and larger planets in or near
the habitable zone of a wide variety of stellar spectral types
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Determine the distribution of sizes and semi-major axes of these
planets
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Identify additional members of each photometrically discovered
planetary system using complementary techniques
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Determine the distributions of semi-major axis, albedo, size, and
density of short-period giant planets
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Estimate the frequency of planets orbiting multiple star systems
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Determine the properties of those stars that harbor planetary
systems
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Mission Design
KEPLER: A Wide FOV Telescope that Monitors 100,000 Stars for 4 years
with Enough Precision to Find Earth-size Planets in the HZ
Use transit photometry to detect Earth-size
planets
 0.95 meter aperture provides enough photons
 Observe for several years to detect the
pattern
of transits
 Monitor stars continuously to avoid missing
transits
 Use heliocentric orbit
Get statistically valid results by
monitoring 100,000 stars
• Use wide field of view telescope
• Use a large array of CCD detectors
21 CCD Modules are the Heart of the Kepler Mission
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DISCOVERY MISSION # 10
Goal: Determine the frequency of Earthsize & larger planets in the HZ of a
variety of star types
Expected science results; hundreds of
Earth-size and larger planets if they are
common
Science Team; 27 from US, Europe, &
Canada
Single science instrument: Photometer
(0.95m aperture, 42 CCDs, 420-890 nm,
passive cooling, focusable primary)
Launch date: October 2007
Heliocentric Earth-Trailing Orbit
Operational life: 4 years
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COMPARISON OF SOLAR SYSTEM TO
OTHER PLANETARY SYSTEMS
Theory of Formation of SS expected to produce inner
terrestrial planets, outer giants, circular orbits.
Observations show that a large fraction of stars have
giant planets in inner orbits with high eccentricity
Implications are that planetary systems can be very
different from SS. SS must have had special
circumstances
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FOV
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Stellar Activity Levels
-3.5
-4
Very Active
2.6 %
Active
27.1%
-4.5
Inactive
62.5%
-5.0
Very
Inactive 7.9%
-5.5
0.5
0.6
0.7
(B-V)
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0.8
0.9
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Signal Detectability
SNR = (Ntran)1/2 (Rp/R*)2 / [(i2+ v2)+ 1/F]1/2.
Where Ntran is the number of transits observed, Rp is the radius of the
planet, R* is the radius of the star, F is the stellar flux measured in
photoelectrons, and (i2+v2) is the signal variance due to instrument noise
and stellar variability.
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MERIT FUNCTION (MF)
Quantifies science value as f(instrument & mission properties)
Merit Function properties
• Models of planetary systems, instrument specs., detection
approach, catalog of all target stars & their properties
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Score is 100 based on currently predicted instrument perform.
a) 60 pts for planets in HZ, 30 pts for planets outside HZ,
10 pts for p-modes
b) Small planets have higher value than bigger (40,20,5,1)
c) Outer planets have higher value than inner planets (r2)
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Adjustable parameters for instrument specs & performance,
mission parameters, and surprises of nature
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SUMMARY
• Graceful degradation
• Greatest sensitivity
– Mission lifetime
– CDPP
• Four year mission provides
comprehensive determination of
frequency of Earth-size and larger planets
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Validation of Discoveries
SNR > 7 to rule out statistical fluctuations
Three or more transits to confirm orbital characteristics
Light curve depth, shape, and duration
Image subtraction to identify signals from background stars
Radial velocity
Medium resolution to rule out stellar companions
High resolution to measure mass of giant planets
High spatial resolution to identify extremely close bkgd stars
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Operations Organization
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Educational & Public Outreach
Lesson plans
Planetarium programs
Amateur obs,
KeplerCam
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PHASE B WORK: PRELIMINARY DESIGN,
RISK MITIGATION, & LONG LEAD ITEMS
Table G-9. Our Initial Risk Assessment/Mitigation Top Risks
Database
Index
Risk Item
Risk
Factor
Mitigation Actions
Risk Type
Likeliness
Impact
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CCD
procurement
delivery
schedule
Develop device specification that permit
high yields (Don't need SOA performance).
Parallel procurement from two vendors.
Early delivery of Engineering Model CCDs
from both vendors with an option to
procure all CCDs from any single vendor
after EM assessment.
Schedule/
Cost
Moderate
(2)
High
(4)
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CCD Module /
electronics
packaging,
metrology and
thermal control
in an FPA this
size.
Extrapolation of present IR&D activity
that addresses packaging of electronics and
CCD focal planes. Early build and test of
Pathfinder FPA using EM CCDs.
Completion of Pathfinder before detail
design and fabrication of Flight FPA.
Extensive thermal model analysis using
TSS and TAK III, updated with test data as
available.
Technical
Moderate
(2)
Significant
(3)
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3
Optics
procurement
Early completion of optics design and
analysis to support preparation of
specifications for early procurement.
Schedule
Moderate
(2)
Moderate
(2)
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Science
Requirements
and Mission
Requirements
Definition
Identify all specifications, ICDs, and plans
which must be complete to support
program schedule. Complete sign-off of
SRD before ATP of Phase B and sign-off of
MRD 2 months after ATP.
Schedule
Moderate
(2)
Moderate
(2)
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SCHEDULE & MISSION STATUS
Phase C/D work has started.
JPL management team is integrated into Kepler team.
17 flight-grade CCD detectors have been received.
Optics are being polished.
FY’05 budget reduction will delay the October 2007
launch.
CY01
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ATP SRR
Phase B
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06
PDR CDR
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Launch
Phase C/D
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End normal
operations
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End extended
operations
Phase E
Phase F
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MISSION COST HISTORY
Proposed in 2000 for 2005 launch at $299M
Concept study for 2006 launch ($
for NIAT, inflation, and increase in booster cost)
Kepler selected but required to slip the launch to 2007 launch
and add JPL  $40M cost increase
Change to full-cost accounting adds $20M
Mission cost at $467M
FY’05 funding reduction causes additional delay and cost
increase
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FOLLOW UP OBSERVATIONS
For false positive elimination and understanding of the Kepler planetary candidates:
1. 300 m/s RV measurements, mr=9-16, avg of 2.5 spectra each
Terrestrial planets
Case 1, no terrestrial planets
~140 false positives (105 go away with DIA after 4 years)
~131 hr on 2m telescope = ~ 22 nights @ $1500/night -> $33K
this price depends on being able to buy 1/2 nights or only using time in June-Aug.
Case 2, ~2160 terrestrial planets found
~2300 candidates
~2155 hr on 2m telescope = ~ 359 nights @ $1500/night -> $538K
Giant planets
~610 candidates
~572 hr on 2m telescope = ~95 nights @ $1500/night -> $142K
2. AO images of 300 candidates mr=9-16 from 1st 90 days
~300 stars
~79 hr = ~13 nights usually need bigger telescope (>= 4m) to get the AO instruments
For characterization to understand the sample of planet bearing stars and their planetary systems:
3. Further characterization of the stars
R= spectra of 300 selected candidates mr=9-12 or brighter, 1 spectrum each
~xx hr on 2 m telescope = ~xx nights = xx/4 nights/year
~9 Kepler observers -> xx/4/9 nights/yr/observer
4. To search for giant members of system with a terrestrial planet
10 m/s RV measurements of 100 selected candidates,
mr=9-12 or brighter, 12 spectra each
~950 hr on 10m telescope = ~158 nights = 40 nights/yr
~4 Kepler observers -> 10 nights/yr/observer
5. .Further characterization is left to the community.
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STELLAR CLASSIFICATION PROGRAM
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