Extreme AO Coronagraph Science with GPI. James R. Graham UC, Berkeley

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1 Extreme AO Coronagraph Science with GPI James R. Graham UC, Berkeley

2 Outline 2 ExAOC science impact Direct vs. indirect planet searches GPI experimental design Our knowledge of exoplanets defines AO design Trade studies ExAOC exoplanet surveys Debris disks Adjunct Science Science Team

3 Why is High Contrast Useful? 3 Exoplanet detection Direct methods explore beyond 5 AU Indirect methods give only M sin i, a & e Circumstellar disks Proto-planetary & debris disks Fundamental stellar astrophysics Large mass ratio main sequence binaries Stellar evolution mass transfer & loss Cataclysmic variables, symbiotic stars & supergiants Solar system Icy moons, Titan & asteroids

4 Direct Detection of Planets 4 Voyager family portrait illustrates the impact of imaging Solar system observations are the initial data point for the theory of planet formation Virtually all we know about exoplanets comes from indirect Doppler methods: M sin i, a & e

5 Planet Searches Doppler surveys have cataloged about 150 planets Indirect searches are limited by Kepler s third law: a = P 2/3 P Jupiter = 11 years P Neptune = 165 years Exo-Jupiters remain undetected A survey of outer regions (a > 10 AU) is impractical using indirect methods 1/r 2 dimming of reflected light renders TPF-C insensitive to planets in Neptune orbits ExAO finds self-luminous planets between 4 40 AU 5 CoDR p. 27

6 Architecture of Planetary Systems 6 Only 5% of stars have Doppler planets Why isn t it 15 to 50%? A diversity of exoplanets Is the Solar System typical? 20% of the Solar System s orbital phase space explored Do A, F or M stars have planets? How do planets form? Core accretion vs. gravitational collapse New questions What is the origin of dynamical diversity? CoDR p. 27

7 Imaging Beyond the Snowline Fast alternative to Doppler Improved statistics 4 40 AU vs AU Find exoplanets at large (> 4AU) semimajor axes Is the solar system is unique? Sample beyond the snow line Reveal if gravitational instability forms planets ( AU) Uncover traces of planetary migration Resolve M sin i ambiguity? Mass from cooling curves Q min = yr 350 yr Q min =1.4 Mayer et al AU 7 CoDR p. 29

8 Exoplanet Atmospheres Eclipses + Doppler data yield mass & radius for a few rare cases Precision astrometry can be used to derive masses synergy with SIM (2010) Direct detection of exoplanet light is the key to unlocking chemical, structural, & evolutionary secrets Exoplanets are the last frontier of classical stellar atmospheres Condensation of H 2 O and NH 3 8

9 Exoplanet Atmospheres 9 Exoplanets occupy a unique location in (log g, T eff ) phase space Over 5 Gyr a 1 M J exoplanet traverses the locus of H 2 O and NH 3 cloud condensation CoDR p. 31 NH 3 Galileo log 10 (g) [cm s-2 ] Jupiter Mass Age T eff [K] Burrows Sudarsky & Lunine 2003 ApJ

10 Detection of Cooling Planets Contrast required detect a exo-jupiter in a 5 AU orbit in the visible is 2 x 10-9 Near-IR contrast is two to three orders of magnitude less Radiation escapes in gaps in the CH 4 and H 2 O opacity at Y, J, H, & K Burrows Sudarsky & Hubeny 2004 ApJ CoDR p. 26 Wavelength µm

11 Experimental Design No simple metric identifies a suitable design For example, minimize residual wavefront error This system works for a handful of bright, nearby stars Could detect a few planets if these stars host exoplanets Reveals nothing about the statistical properties of exoplanets How do we maximize scientific productivity of ExAOC? Large multi-dimensional trade space Contrast vs. limiting magnitude Field of view (inner and outer working distances) Observing wavelength Spectral resolution Speckle suppression Adopt number of detected planets as a metric Define selection effects for exoplanet mass, age or spectral type 11

12 Exoplanet Populations 12 CoDR p. 43

13 An Example 13 ExAOC configuration AO r 0 = 100 cm 2500 Hz update rate 13 cm subapertures R = 7 mag. limit Coronagraph Ideal apodization Science camera Broad band H No speckle suppression Target sample R < 7 mag field stars (< 50 pc) CoDR p. 46 Results Doppler ExAOC 110 exoplanets (6.5 % detection rate) Semimajor axis distribution is complementary to Doppler exoplanets

14 An Example 14 ExAOC configuration AO r 0 = 100 cm 2500 Hz update rate 13 cm subapertures R = 7 mag. limit Coronagraph Ideal apodization Science camera Broad band H No speckle suppression Target sample R < 7 mag field stars (< 50 pc) CoDR p. 46 Astrometric Results Doppler ExAOC 110 exoplanets (6.5 % detection rate) Semimajor axis distribution is complementary to Doppler exoplanets

15 Limiting Mag. & Detection Rate Trade Scientific success of Doppler surveys derive from the large number of planets detects diversity is the rule With ~ 100 planets trends are only just becoming apparent Statistical trends only emerge from significant samples 3 properties 5 bins per property 4-σ counting statistics = 240 planets Guide star magnitude (I ) No. of target stars No. of planets detected* AO hit rate (%)* < (1) 50 (25) < (13) 20 (20) 15 OCDD p. 25 < 6 < (82) 247 (208) 10 (10) 6.5 (5.4) * 18-cm subapertures Numbers in parenthesis are for 12-cm

16 Observing Wavelength Trade Clear dichotomy between observing wavelength/speckle suppression High performance near-ir system Operates at ambient temperature (270 K) Modest speckle suppression ( 1/16 1/32) Low background/cryogenic L-prime system No speckle suppression Atmosphere & telescope background always dominate Number of exoplanets 16 CoDR p. 48

17 Speckles & Spectral Resolution Spectral resolution is necessary for Atmosphere diagnostics T eff and log(g) Speckle suppression An IFU with λ/δλ 40, Δλ 20% supports Classification of atmospheres > 10 Speckle suppression for flat-spectrum sources > 100 speckle suppression for T dwarf spectrum 17 CoDR pp. 33 & 70

18 ExAOC Field Star Survey Field survey with the baseline CoDR system Cerro Pachon seeing 18 cm subapertures, I = 8 mag. limit Adaptive modal gain control 2500 khz maximum update Apodized pupil Lyot coronagraph IFU withλ/δλ 40, Δλ 20% ( 16 speckle suppression) No cut on stellar age Exposure time 1 hour, 5-σ detection threshold 18 CoDR p planets discovered in field star survey

19 Young Star Survey Young exoplanets are bright Ca II H&K selected sample (<2 Gyr) boosts detection rate to 36% Relax contrast demands Probe further down the exoplanet mass sequence Field star exoplanets N * = 170 η = 36% Young association exoplanets 19 OCDD p. 33

20 Debris Disks Gravitationally sculpted disks provide key evidence for exoplanets Kalas Graham & Clampin 2005 Nature, 435, 1067 Morphology of dust trapped in libration points provides key to masses and eccentricities of exoplanets Surface brightness,color, phase function, and polarization indicates quantity composition and grain size distribution Fomalhaut debris disk F606W + F814W HST/ACS coronagraph µ 20 mag arc sec-2 µ/µ High-mass exoplanet in a low eccentricity orbit Synergy with ALMA Probe disjoint dust grain populations 20 CoDR p. 36

21 Debris Disks Only a handful of debris disks have been imaged in scattered light Handful of high spatial resolution images Few non-edge on disks AU Mic/Keck AO 21 Fitzgerald Kalas & Graham 2005

22 Speckle Suppression for Debris Disks PSF subtraction AU Mic/Keck AO Polarimetry AU Mic/ACS polarimeter I Q U 22 CoDR p. 41

23 Dual Channel Polarimetry Simulations AU Mic/50 τ = 4 x 10-5 θ = 90, 70 & 30 Edge-on disk is easily detected in Stokes I in 1 hour Progressively less visible in Stokes I in non edge-on configurations Dual channel polarimetry reveals face-on disks 90 23

24 Dual Channel Polarimetry Simulations AU Mic/50 τ = 4 x 10-5 θ = 90, 70 & 30 Edge-on disk is easily detected in Stokes I in 1 hour Progressively less visible in Stokes I in non edge-on configurations Dual channel polarimetry reveals face-on disks 70 24

25 Dual Channel Polarimetry Simulations AU Mic/50 τ = 4 x 10-5 θ = 90, 70 & 30 Edge-on disk is easily detected in Stokes I in 1 hour Progressively less visible in Stokes I in non edge-on configurations Dual channel polarimetry reveals face-on disks 30 25

26 Adjunct Science General utility of high contrast Binaries Main sequence binaries L & T dwarfs White dwarf companions Evolved stars Mass loss from red giants, proto-planetary nebulae Symbiotic stars RY Scuti R. Campbell Solar system Geomorphology of icy/rocky moons Broad opportunity for serendipity 26

27 International Science Team Adam Burrows (UofA) Constraining effective temperatures and surface gravities. Theoretical uncertainties in exoplanet detection. Eugene Chiang (UCB) Radiative transfer & dynamics of debris disks René Doyon (UdM) Optimal detection techniques for exoplanets James Graham (UCB) Project Scientist. Coordinate science team activities. Monte Carlo trade-study tools. Traceability of science requirements. Doug Johnstone (HIA) Interpretation of structure debris disks, including planetary & nonplanetary signatures. Paul Kalas (UCB) Detection of disks & selection of debris disk 27 target stars James Larkin (UCLA) Multi-color exoplanet detection. Bruce Macintosh (LLNL) PI Deliver estimates of integrated system performance. Franck Marchis (UCB) Solar system science. Geoff Marcy (UCB) Young star catalogs. Algorithms for measurement of orbital elements Ian Mclean (UCLA) Polarization science Ben Oppenheimer (AMNH) Detection & characterization of exoplanets. Jenny Patience (Caltech) Catalog young associations & moving groups. Age of field stars. Yanqin Wu (Toronto) Imprint of planets on disks. Vol 3 p. 21