Click to edit Master title style

W F I R S T

An extraordinary science investigation of new worlds and new horizons

WFIRST Preparatory Science Kickoff

2015-03-12 Dominic Benford

WFIRST Exoplanet Imaging: Datacubes, Community Challenges, and the

Starshade Study

Dr. Margaret Turnbull, SETI Institute Carl Sagan Center for the Study of Life in the Universe

Click to edit Master title style WFIRST Coronagraph SIT Turnbull Team Members

Harnessing the Power of the WFIRST-Coronagraph A Coordinated Plan for Exoplanet and Disk Science

Dr. Margaret Turnbull (SETI Institute)

David Ciardi (NExScI / Caltech) Hannah Jang-Condell (Wyoming) Stephen Kane (SFSU) Nikku Madhusudhan (Cambridge) Aki Roberge, Avi Mandell, Michael McElwain (NASA GSFC) Stuart Shaklan, Renyu Hu (JPL) Chris Stark, Laurent Pueyo, William Sparks (STScI) Philip Hinz (Arizona)

Click to edit Master title style Target Stars

Team

“Truth” Data Team Build Known, Hypothetical

Planetary Systems with Dust,

Background

SRD Team

Create WFIRST Coronagraph Scientific

Requirements

Planet Atmospheres

Team

Baseline Performance

Instrument Simulator Team

Conduct “Blind” Community Data

Challenges

In-House Source Extraction and

Spectral Retrieval

Turnbull SIT Macintosh SIT WFIRST

Coronagraph SIT Synergy

Spectral Library System

Descriptions

Simulated Raw Data

Rp vs Teq

Cp

Data Cubes

Science Yield

2016 DELIVERABLE

Click to edit Master title style

SRD Team

Create WFIRST Coronagraph Scientific

Requirements

Baseline Performance

Turnbull SIT Macintosh SIT WFIRST

Coronagraph SIT Synergy

Science Yield

DRM Team

2016 DELIVERABLE

IWA, Fp/F*, eta_planet

Click to edit Master title style Planets of Interest: WFIRST Detection Space M

inim

um D

etec

tabl

e P

lane

t Siz

e (E

arth

Rad

ii)

Separation, in units of Earth-Equivalent Insolation Distance 1

1

10

10 0.1

0.1

Trad

ition

al H

abita

ble

Zone

planets at quadrature, AB=0.3, 100 mas IWA, 1.6” OWA Imag

e C

redi

t: M

. Tur

nbul

l

E V

J

S

Click to edit Master title style Planets Around Other Targets: WFIRST Bands “R

-I”

“B-V”

ß EARTHS à

Click to edit Master title style

Jupiter

Venus Earth

Mars

30 AU

Neptune

Inner 12 AU x 12 AU

Solar System w/out Sun λ = 0.55 µm

Credit: A. Roberge & the Haystacks team

Finding the Needles in the Haystacks Spectral image cubes: 0.3 µm – 2.5 µm Contain star, planets, consistent dust

Option to add galactic & extragalactic background sources

Click to edit Master title style Potentially Serious Problem: At V ~ 27th magnitude, WFIRST will also detect the deep background.

Click to edit Master title style Stellar Target Data

+

Known and Hypothetical

Planets

+

Dust

+

AstrophysicalBackground

Spectral Data Cubes

Instrument Response Simulator

Blind Retrieval Exercises: Community Challenges and

In-House Studies

WFIRST CGI: Preparing for Discovery

Click to edit Master title style

Astrophysical Constraints

•  ηplanet •  ηexozodi

•  Planet sizes •  Albedos •  Phase functions

Technical Requirements

•  Telescope diameter •  Contrast •  Contrast floor •  Inner working angle •  Outer working angle •  Total throughput •  Overheads

Mission yield calculations

Design reference mission (DRM)

Observational Requirements

•  Central wavelength •  Total bandpass •  Spectral resolution •  Signal-to-Noise •  Observing strategy

0.4 0.5 0.6 0.7 0.8 0.9 1.0Wavelength (µm)

10−10

10−9

10−8

10−7

Plan

et F

lux

/ Sta

r Flu

x

0.8 AU Jupiter2 AU Jupiter

Water world, 100% clouds1 AU NeptuneJupiterSub−Neptune (2 REarth)Super−Earth (1.4 REarth)Earth

Stark et al. (2014)!Stark et al. (2015)!

Click to edit Master title style

Exoplanet Exploration Program

Click to edit Master title style Exo-S Team Members

STDT S. Seager, Chair (MIT) M. Thomson (NASA-JPL) M. Turnbull (GSI) W. Sparks (STScI) S. Shaklan (NASA-JPL) A. Roberge (NASA-GSFC) M. Kuchner (NASA-GSFC) N. J. Kasdin (Princeton) S. Domagal-Goldman (NASA- GSFC) W. Cash (Colorado)

JPL Design Team K. Warfield, Lead D. Lisman C. Heneghan S. Martin D. Scharf R. Trabert D. Webb E. Cady R. Baran P. Zarifian S. Krach B. Hirsch

Exo-S Final Report to NASA APS - March 18, 2015

Click to edit Master title style Starshade Basics

�  PRO: Contrast and IWA decoupled from telescope aperture size �  PRO: No outer working angle �  PRO: Few reflections = high throughput, broad wavelength bandpass �  PRO: Starlight does NOT enter telescope

�  High quality telescope not required, wavefront correction unnecessary

�  CON? Retargeting requires long starshade slews (days to weeks) Exo-S Final Report to NASA APS - March 18, 2015

Inner Working Angle (IWA)

Telescope aperture diameter 2.4 m

25 to 50 Mm separation

30 m or 34 m diameter starshade

Click to edit Master title style A WFIRST-Starshade Rendezvous Mission �  Starshade launches for a rendezvous with an existing

telescope �  Telescope: WFIRST/AFTA 2.4-m diameter �  Starshade: 34 m diameter �  Orbit: Earth-Sun L2 (assumption for the purposes of the

Exo-S study) �  Retargeting: by the starshade spacecraft with chemical

propulsion �  Three year Class C mission �  Minimal impact to current mission design

�  No stringent requirements are imposed on the WFIRST/AFTA spacecraft

�  No new instrument, only modification to the existing coronagraph Exo-S Final Report to NASA APS - March 18, 2015

Click to edit Master title style Take-Away Message

Exo-S Final Report to NASA APS - March 18, 2015

WFIRST/AFTA can be leveraged for a unique and timely opportunity

�  Rendezvous Mission can access up to 50 unique target stars for exoEarths in the habitable zone

�  Minimal modification needed for starshade readiness

�  Starshade technology is on track for TRL-5 by 2017 and for new start by 2018, but not fully funded

�  Mission cost ~ $627M, CATE raised no issues with schedule