LBTI ORR Pre-Briefing to the Board

April 14, 2015

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BoardName Affiliation

Dr. Scott Gaudi, Chair Ohio State University

Dr. Theo ten Brummelaar Georgia State / CHARA

Dr. Sam Ragland WM Keck Observatory (WMKO)

Dr. Gerard van Belle Lowell Observatory

Dr. Marc Kuchner Goddard Space Flight Center (GSFC)

Dr. Ellyn Baines Naval Research Laboratory (NRL)

ObserversHashima Hasan NASA, Program ScientistDebra Wallace NASA, Deputy Program ScientistMario Perez NASA, Program ExecutiveGary Blackwood JPL, Exoplanet Exploration Program Office

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Org Chart

Program Science Office

Scientist - Dr. S. Unwin

Exoplanet Exploration Program Office

Program Manager – Dr. G. BlackwoodProgram Chief Scientist – Dr. W. Traub

Program Chief Technologist – Dr. N. Siegler

Program Engineering Office

K. Warfield

Astrophysics Division, NASA HQ

Program Executive – M. PerezProgram Scientist – Dr. Hashima Hasan

Deputy PS – Dr. Debra Wallace

ExoPlanet TAC1

Dr. A. BossCarnegie Institute

Large Binocular Telescope Interferometer (LBTI)

Manager – Dr. M. Jeganathan, JPLProj Scientist – Dr. R. Millan-Gabet, Caltech

PI – Dr. P. Hinz, UAManager – S. H. Bailey, UA

Astrophysics Division, NASA HQ

Director – Dr. P. HertzDep. Director/Program Director – A. Razzaghi

NASA Exoplanet Science Institute (Caltech)

Exec. Director – Dr. C. BeichmanDeputy Director – Dr. R. Akeson

Manager – Dr. D. Imel

ORR Success Criteria

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1. The ORR performance requirements [12 zodi, 0.4 mJy, and 35 in-guide stars] are sufficient to meet the PLRA science objectives [inform future mission design and sensitivity >10x higher than state of the art]

2. LBTI ORR performance requirementsa) LBTI demonstrates 12 zodi sensitivity (1s, single star measurement, PLRA zodi model).b) In-guide plan (available nights) and assumptions (efficiencies and current capability) for SVP and HOSTS

are documented and the science scope (<2 zodi uncertainty on median) are all consistent.c) Credible plans* documented to meet PLRA threshold performance requirements (6 zodi,

0.3 mJy) by end of science validation phase with risk that is medium or lower.

3. LBTI science data management planning and procedures meet all PLRA requirements4. The necessary interferometer operations plans and procedures are complete, documented

and in place, and under configuration management5. The necessary pipeline processing algorithms, plans and procedures are complete,

documented and in place, and under configuration management6. The necessary staffing is in place and training has taken place7. Project risks are documented and acceptable8. During SVP, UA is ready to assume responsibility for LBTI operations and data delivery; and

NExSci is ready to assume responsibility for archive

* scope, supporting analysis, baseline schedule, personnel, contingency, risks

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Intended Results of this Briefing

1. The Board understands the relationship between ORR performance requirements and the PLRA baseline science objectives, baseline science requirements and threshold science requirements

2. The Board understands the analysis basis for the success criteria, in terms of zodi sensitivity and # stars surveyed, to meet the Mission Success Criteria documented in the PLRA (inform the design of a future NASA space mission and sensitivity at least an order of magnitude higher than the current state of the art)

ORR Success Criteria

• ORR success criteria derived from LBTI Programmatic Requirements in§4 of PLRA– Emphasis on Threshold requirements instead of

Baseline requirements

• Other Sections less important– Section 2 lists science and technology objectives, and defines zodi

unit• LBTI Baseline Science Objectives (§2.1) are restated as Mission Success Criteria

(§4.3)

– Section 3 discusses roles and responsibilities & data rights– Sections 5-11 not relevant to ORR

L0 – Mission Success Criteria (§4.3)A. Provide measurements necessary to inform the design of a

future NASA space mission to directly image and characterize exo-Earths around nearby main sequence stars.

B. Provide measurements of exozodi levels around nearby main sequence stars with sensitivity at least an order of magnitude higher than the current state of the art.

L1 - Performance Requirement§4.1.2 Threshold success criteria:

Survey the exozodiacal flux of 50 nearby stars with a 1s noise equivalent corresponding to six times the signal due to the zodiacal dust in our own planetary system (six zodi).

Complete the HOSTS survey within 4 years after completion of commissioning.

C. Measure the exozodiacal flux with a 1s noise equivalent corresponding to six times the signal due to the zodiacal dust in our own planetary system (six zodi).

D. Survey 50 nearby stars within 4 years after completion of commissioning

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L2 - Instrument Requirements (4.1.4)

E. Photometric sensitivity (1s ): 0.3 mJy, over bandpass 10-12.5 (standard N’ filter), to be reached during the elementary per-star observing sequence

F. Calibrated null stability (1s) of 1.5x10-4 (planned null depth 1x10-3),2 to be reached for a full calibration cycle.

G. The elementary observing sequence includes measurements to calibrate the background and provide flux normalization, and is expected to last about 30 min with 30% duty cycle, resulting in about 10 min of integration time.

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Motivation for relaxing ORR Entrance Criteria

• Eighteen of fifty HOSTS nights have already been consumed for commissioning.

• LBTI best performance to date is 15 zodi (500 ppm calibrated null uncertainty)– 12 zodi (400 ppm calibrated null uncertainty) achieved with additional

target-calibrator sequence (2x threshold requirement)

• How best to proceed with allocated resources– 32 nights available (in FY16 and FY17; in-guide plan)– Better understand the impact of Exo-zodi median level

uncertainty on the design and predicted science yield of future exo-Earth Direct Imaging missions

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Exozodi impact on planet Detection

• Study carried out by Mennesson and Stark on– Impact of “smooth” exo-zodi level uncertainty on the

predicted science yield (sensitivity) of a future exo-Earth imaging mission

– Impact of exo-zodi level uncertainty on (predicted) ability to discriminate exoplanets from exozodi clumps

• Conclusion: Exozodi clumps lead to greater confusion in interpreting observations – cannot be mitigated by integration time

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False positives of exozodi clumps

If exo-zodi level is around 10-20x higher than in solar system, resonant dust ring structures could be brighter than an exo-Earth at 1AU (Figure from Defrere et al. 2012)

1 zodi

5 zodi

10 zodi

20 zodi

50 zodi

100 zodi

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Exozodi clumps drive requirements of future exo-Earth missions

• Current simulations (Stark, Kuchner, Defrere, etc.) suggest that at the 10-20 zodi level, dust clumps could outshine the reflected signal of an Earth-like planet and be very close to it, creating a major source of confusion and false positives for a future mission– The exact brightness and location of these clumps will be stellar

system specific (function of Mp, ap, rdust)

• In order to properly assess this risk, the median exozodi level should be measured down to a fraction of this 10-20 zodi confusion threshold

• This “confusion uncertainty” (bright clumps) issue is likely more important than the sensitivity uncertainty, and should drive the LBTI performance requirement

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Derived LBTI Survey Requirements• How does the maximum tolerable uncertainty on the median exozodi level

of solar type stars fit in the PLRA space of number of stars observed (N) vs measurement uncertainty per star (sZ )

• If N stars are observed with an individual (1s) uncertainty of sZ zodis, we assume* that the resulting (1s) uncertainty on the median zodi level for that class of stars is then sZ /sqrt(N)

• E.g., aiming for a median uncertainty of sZ /sqrt(N) < 2 zodis means N > s2

Z /4, which is the region left of the line below

LBTI Requirements to Inform Design of Future Missions

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4 Zo

di

2 Zo

dis (

1) s

Unce

rtain

ty o

n

Med

ian

Exo-

Zodi

Leve

l

Low Confusion Uncertainty

(Exozodi Well Characterized)

High Confusion

Uncertainty

Medium Confusion

Uncertainty

Keck Survey Results

Exozodi Poorly Characterized

Very High Confusion

Uncertainty

Bertrand Mennesson, 2014

LBTI PLRA Threshold

LBTI Today 24

Zod

i

16 Z

odi

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State of the Art – Keck Nuller• Demonstrated performance of 2000-3000 ppm calibrated null

uncertainty – Colavita et al. 2009, PASP, 121, 1120

• Surveyed 20 stars and demonstrated 24 zodi, 1s uncertainty on median exo zodi level‐– Mennesson et al. 2014, ApJ, 797, 119

• For solar type stars, using PLRA ring model, this translates to 130-200 zodi, 1s, single star measurement error

• 150 zodi 1s, typical single star measurement error• 24 zodi, 1s uncertainty on median exo zodi level‐

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Recommendations• Adopt a top-level requirement on the median exo-zodi level

uncertainty to inform future exo-Earth missions– determine the median exo-zodi level of nearby solar type stars with a

1s uncertainty of 2 zodi (green region)– For statistical reasons, observations of >20

solar-type stars is required– Provides a framework for assessing performance against the two main

LBTI survey parameters (number of stars and measurement uncertainty per star)

• Continue to work towards achieving threshold requirements during science validation phase (SVP, ~1 year duration)– Assess LBTI performance at end of SVP in a Science Operation

Review (SOR)

PLRA Compliance

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§ SuccessCriteria

Now (ORR)

End of SVP

In-guidePlan

(FY17)

With lien

(FY18)L0 4.3 A: 10x better L0 4.3 B: inform missions * *

L1 4.1.2 C: 6 zodi, 1s

L1 4.1.2 D: 50 star survey

L2 4.1.4 E: 0.3 mJy sens.

L2 4.1.4 F: 1.5x10-4 null stb

L2 4.1.4 G: 30% efficiency

* Projection (when survey is complete)

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Data Requirements (§4.2) H. LBTI Data (NOMIC-Nulling and LMIRCam) to be archived by NExScI and

publicly distributed when the periods of exclusive use (§3.4.3) expire.

• Three types of data products shall be archived; the delivery time scales in each case are appropriate to the needs of the HOSTS survey:

I. Level 0: Clean and merged raw science data; delivered from LBTI to NExScI within 72 hrs of observation.

J. Level 1: Internally calibrated science data, delivered from the observatory to NExScI within 20 work days of observation. Internally calibrated data consists of: cleaned Level 0 images (dark subtracted, bad pixels removed, flat fielded, background subtracted) and files containing derived quantities (null and stellar fluxes, associated errors, diagnostic quantities).

K. Level 2: Externally calibrated science data, delivered from the observatory to NExScI within 40 work days of observation. Externally calibrated data files contan fully calibrated nulls and associated errors (effects of instrument’s transfer function removed), and result from processing multiple Leve 1 files obtained on the target star and its calibrator stars.

PLRA Compliance

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§ SuccessCriteria

Now (ORR)

End of SVP

In-guideplan

With lien

(FY 18)

L1 4.2.1H: Archive & distribute

L2 4.2.2 I: L0 data in 72 hrs

L2 4.2.2 J: L1 data in 20 days

L2 4.2.2 K: L2 data in 40 days

ORR Success Criteria

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1. The ORR performance requirements [12 zodi, 0.4 mJy, and 35 in-guide stars] are sufficient to meet the PLRA science objectives [inform future mission design and sensitivity >10x higher than state of the art]

2. LBTI ORR performance requirementsa) LBTI demonstrates 12 zodi sensitivity (1s, single star measurement, PLRA zodi model).b) In-guide plan (available nights) and assumptions (efficiencies and current capability) for SVP and HOSTS

are documented and the science scope (<2 zodi uncertainty on median) are all consistent.c) Credible plans* documented to meet PLRA threshold performance requirements (6 zodi,

0.3 mJy) by end of science validation phase with risk that is medium or lower.

3. LBTI science data management planning and procedures meet all PLRA requirements4. The necessary interferometer operations plans and procedures are complete, documented

and in place, and under configuration management5. The necessary pipeline processing algorithms, plans and procedures are complete,

documented and in place, and under configuration management6. The necessary staffing is in place and training has taken place7. Project risks are documented and acceptable8. During SVP, UA is ready to assume responsibility for LBTI operations and data delivery; and

NExSci is ready to assume responsibility for archive

* scope, supporting analysis, baseline schedule, personnel, contingency, risks

0.

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Summary

• Exozodi simulation and analysis provides a basis to quantify LBTI science objective of informing the design of a future NASA space mission to directly image and characterize exo-Earths

• Request Board evaluate whether the ORR performance requirements meet the PLRA science objectives/mission success criteria

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Backups

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Acronym List

HOSTS Hunt for Observable Signatures of Terrestrial Systems

KI or KIN Keck Interferometer Nuller

L0, L1, L2, L3 Level 0, 1, 2, 3

LBT Large Binocular Telescope

LBTI Large Binocular Telescope Interferometer

LEECH LBTI Exoplanet Exozodi Common Hunt

PLRA Program-Level Requirement Appendix

SOR Science Operations Review (end of SVP)

SVP Science Validation Phase (post-ORR to SOR)