Glenn Schneider Steward Observatory, University of Arizona (NICMOS/IDT) High Contrast Imaging and The Disk/Planet Connection

Asymmetries (radial & azimuthal): May implicate low-mass perturbers (planets) from: Rings, Central Holes, Gaps, Clumps, Arcs, Arclets Help Elucidate the scattering & physical properties of the grains. Observing scattered light from circumstellar debris has been observationally challenging because of the very high Star:Disk contrast ratios in such systems B.A. Smith & R.J. Terrile 6" radius coronagraphic mask, Las Campanas (discovery image) Until very recently the large, and nearly edge-on disk around  Pictoris remained the only such disk imaged.  Pictoris Resolved imaging spatial distribution of dust/debris. Direct (Scattered Light) Imaging of Dusty Debris

The HUBBLE Legacy Breaking the Low Contrast Paradigm

Diffraction Limited Imaging in Optical/Near-IR > 98% Strehl all  s Highly STABLE PSF Coronagraphy: NICMOS STIS, ACS NIR High Dynamic Range Sampling NICMOS/MA:  mag=19.4 (6 x 4m) Background Rejection 1.6  m: ~10 -6 pix 1” 1.1  m: ~10 -5 in 2”-3” annulus Intra-Orbit Field Rotation TODAY HST Provides a Unique Venue for High Contrast Imaging HST is a stepping stone for super- high contrast * imaging * Background Rejection 10 9— 10 10

Terrestrial planets form Clearing of inner solar system, formation of a Kuiper cometary belt? 10 8 yrs 10 9 yrs Era of heavy bombarment by comets Current age of the Sun: 5x10 9 yrs.  Persei Sun Hyades Tucanae Assoc Pleiades Primary Dust (≤  m) Secondary Dust (≥ Locked to Gas Collisional erosion Clearing Timescales: P-R drag few 10 Rad. Pressure: ~ 10 From: R. Webb Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions  m) 6 4 Rocky cores of giant planets form accrete gaseous atmospheres TW Hydrae rys 10 7 Assoc Giant planets Planet-Building Timeline HST Vis/NIR High Contrast Beyond HST Vis/UV Super-High Contrast

Young Extra-Solar Planet* & Brown Dwarf Companions * < few x 10 6 yr at 1” Circumstellar Disks f disk /f * > few x at 1”  > 50 mas Scientific Areas of Investigation Enabled With Today’s Capabilities on HST via PSF-Subtracted Coronagraphic Imaging

Moving Beyond HST into the Super-High Contrast Regime Exosolar Planet Imaging & Spectroscopy: few x 10 6 Myr at 1” > 10 9 yr (solar age) at 1” Disk Imaging & Spectroscopy: f disk /f * > few x at 1” ≤ at 1”  > 50 mas a few mas (sub-AU at 200pc) OPTICAL CONFIGURATIONS Coronagraphy Polarimetric Nulling Nulling Interferometry Wavefront Correction Station-Keeping Occulters Interferometric Arrays TECHNOLOGICAL CHALLENGES Micro-Roughness of Optical Surfaces Particulate/Contamination Control Stray Light Management & Control Pupil Apodization (and Shaping) Metrological Tolerancing & Stability Wavefront/Mirror Sensing & Control

The Dusty Disk/Planet Connection Current theories of disk/planet evolution suggest a presumed epoch of planet-building via the formation and agglomerative growth of embryonic bodies, and the subsequent accretion of gaseous atmospheres onto hot giant planets, is attendant with a significant decline in the gas-to-dust ratios in the remnant protostellar environments. few megayears to a few tens of megayears In this critical phase of newly formed (or forming) extra-solar planetary systems, posited from a few megayears to a few tens of megayears, the circumstellar environments become dominated by a second-generation population of dust containing larger grains arising from the collisional erosion of planetesimals.

< 1Myr Proplyds in Orion and…Substellar Objets to ~ 10 M jup

HH30 Obscured GM AUR Unembedded Direct Image Coronagraph + PSF Subtraction ~ 1— few Myr

Coronagraph + PSF Subtraction

Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions Planet-Building Timeline HH 30

Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions Planet-Building Timeline Rocky cores of giant planets form

Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions accrete gaseous atmospheres TW Hydrae rys 10 7 Assoc Giant planets A

Terrestrial planets form Clearing of inner solar system, formation of a Kuiper cometary belt? 10 8 yrs 10 9 yrs Era of heavy bombarment by comets Current age of the Sun: 5x10 9 yrs.  Persei Sun Hyades Tucanae Assoc Pleiades Primary Dust (≤  m) Secondary Dust (≥ Locked to Gas Collisional erosion Clearing Timescales: P-R drag few 10 Rad. Pressure: ~ 10 From: R. Webb Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions  m) 6 4 Rocky cores of giant planets form accrete gaseous atmospheres TW Hydrae rys 10 7 Assoc Giant planets Planet-Building Timeline

Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST. HR 4796A (A0V), ~ 8 Myr A 70AU radius ring, ~ 12 AU wide ring of very red material, exhibiting strong forward scattering and ansally asymmetric hemispheric flux densities.

A 400AU radius disk, with a broad, partially filled asymmetric gap containing a “spiral” arclet. HD A (Herbig Ae/Be) ~ 5 Myr Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.

TW Hya (K7) “Old” PMS Star Pole-on circularly symmetric disk with a break in its surface brightness profile at 120 AU (2”). Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.

TW Hya (K7) “Old” PMS Star Pole-on circularly symmetric disk with a break in its surface brightness profile at 120 AU (2”). and, possibly, a radially and azimuthally confined arc-like depression. Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.

HR 4796A 1.1  m 0.58  m

Ansal Separation (Peaks) = 2.107” ± ” Major Axis of BFE = 2.114” ± " P.A. of Major Axis (E of N) = 27.06° ± 0.18° Major:Minor Axial Length = ( ± 0.034): 1 Inclination of Pole to LOS = 75.73° ± 0.12° Photocentric Offset from BFE(Y) = " ± " Photocentric Offset from BFE(X) = " ± " HR 4796A RING GEOMETRY (Least-Squares Isophotal Ellipse Fit)

Brightness (Normalized to NE Ansa) HR 4796A Circumstellar Debris Ring - WIDTH FWHM ring = 0.184” FWHM: 12.3±0.7AU 8.7% D ring 1-e -1 = 0.265” PSF point source = 0.070” Measured = 0.197” WIDTH AT NE ANSA 1-e -1 : 17.7±10.1AU 12.5% D ring * 20% inner:outer fall-off asymmetry *

Ansal Separation (Peaks) = 2.107” ± ” Major Axis of BFE = 2.114” ± " P.A. of Major Axis (E of N) = 27.06° ± 0.18° Major:Minor Axial Length = ( ± 0.034): 1 Inclination of Pole to LOS = 75.73° ± 0.12° Photocentric Offset from BFE(Y) = " ± " Photocentric Offset from BFE(X) = " ± " RING GEOMETRY - Least-Squares Isophotal Ellipse Fit

“FACE-ON” PROJECTION - With Flux Conservation

Spatially Resolved Relative PHOTOMETRY of the Ring

N-Sigma Brightness Ratio (Percent) NW:SE Surface Brightness Anisotropy

N-Sigma Brightness Ratio (Percent) Front:Back Surface Brightness Anisotropy

Broad Colors of the HR 4796A Debris Ring [50CCD]-[F110W]=0.55±0.09 [50CCD]-[F160W]= Intrinsically red grains Consistent with collisionally evolved population of particle sizes > few microns Not primordial ISM grains Similar intrinsic colors to TNOs in our solar system [V]-[J]=+1.07* Consistent with laboratory* irradiation experiments on a variety of organics to study reddening of D & P type asteroids with distance From Sun. *Barucci et al (1993); Andronico et al (1987)

Collapsing protostar forms proto- planetary disk 10 6 yrs Taurus, Ophiuchus star forming regions  m) 6 4 Rocky cores of giant planets form accrete gaseous atmospheres TW Hydrae rys 10 7 Assoc Giant planets Planet-Building Timeline

Log 10 Age (years) 80M jup 14M jup JUPITER SATURN STARS (Hydrogen burning) BROWN DWARFS (Deuterium burning) PLANETS 200M jup Evolution of M Dwarf Stars, Brown Dwarfs and Giant Planets (from Adam Burrows) Log 10 L/L sum sun Cooling Curves for Substellar Objects

CORONAGRAPHICCOMPANIONDETECTION (Multiaccum) Imaging at two S/C orientations (in a single HST visability period). Background objects rotate about occulted Target. PSF structures and optical artifacts do not. TWA6. Two Integrations: Median of 3 Multiaccum Each  Roll = 30°  Time = 20 minutes

Above: Coronagraphic Images  Roll: 30° Above: Coronagraphic Images  Roll: 30° Left: Difference Image Same display dynamic range H “companion” = 20.1  H = 13.2,  =2.5” At  =2.5” background brightness is reduced by an ADDITIONAL factor of 50 over raw coronagraphic gain (of appx 4). Each independent image of TWA6“B” is S/N ~20 in difference frame.

Imperfections in PSF-subtractions result in residuals expected from pure photon noise. Systematics: OTA “Breathing” Target Re-centration Coron. Edge Effects Mechanical Stability

Detectability and Spatial Completeness (  ) Dependence via Model PSF Implantation (  ) Dependence via Model PSF Implantation Observed Model * Nulled Implant * TinyTim 5.0 HST+NICMOS Optical Model - Krist

Detectability: (  ) Dependence via Model PSF Implantation

% Recovered Flux S/N (Positive Implant Only) Photometric Efficacy & Statistical Significance

Detectability: (  ”  ) Dependence via Model PSF Implantation

Arc Seconds PSF FWHM = 0.16" NICMOS F160W 25 OCT 1998 Camera 2 (0.076"/pixel) Coronagraph (0.3" radius) Integration Time =1280s TWA6 Image Combination: S/N TWA6B = 35

H-Band (F160W) Point-Source Detectability Limits Two-Roll Coronagraphic PSF Subtraction 22m Total Integration  H(5  ) =  ”  ” 2 {M&K Stars}.  Read Noise DominatedPhoton Noise Dominated H=6.9

Arc Seconds PSF FWHM = 0.16" NICMOS F160W 25 OCT 1998 Camera 2 (0.076"/pixel) Coronagraph (0.3" radius) Integration Time =1280s TW Hya Assn K7 primary, D = 55pc Age = 10 Myr  =2.54”, 140AU  H =13.2 (L B/A )[H]=5 x Habs = 16.6 Implies: Mass ~ 2 Jupiter Mass ~ 2 Jupiter T eff ~ 800K T eff ~ 800K IF Companion... S/N TWA6B = 35 TWA 6A/B

Arc Seconds PSF FWHM = 0.16" NICMOS F160W 25 OCT 1998 Camera 2 (0.076"/pixel) Coronagraph (0.3" radius) Integration Time =1280s Confirmation (or Rejection) by Common Proper Motion … possible via ground- based adaptive optics imaging with a sufficiently long temporal baseline. Keck II + AO imaging. Courtosy of B.Macintosh, LLNL

Anomaly or Bias? A Jovian > 140 AU? RV Surveys suggest ~ 5% MS * s have 0.8—8 Mjup d < 3AU from their primaries. NOT Where Giant Planets are found in our own Solar System WHY ARE THEY THERE? Posited*: Mutual interactions within a disk can perturb one young planet to move into a < 1AU eccentric orbit (as inferred from RV surveys), and the other… Ejected (but bound) to very large separations, > 100AU Cannot be observationally tested with HST-like capabilities, requires “Super-High” contrast imaging. * e,g., Lin & Ida (ApJ, 1997); Boss (2001, IAU Symp 202)

Inner Regions of Evolved Disks Cannot yet be probed in scattered light. Yet, as inferred from mid-IR: An inner tenuous component of warm zodi-like dust may be confined within a few AU of HR 4796A. 12–20  m thermal emission is contained completely within the large inner “hole” of HD A. What evolutionary and dynamical interactions may be going on between unseen planets and unseen dust which will shape these systems? Requires “Super-High” contrast and resolution.

Log 10 Age (years) 80M jup 14M jup JUPITER SATURN STARS (Hydrogen burning) BROWN DWARFS (Deuterium burning) PLANETS 200M jup Log 10 L/L sum sun HST Has Sampled Only the Low-Hanging Fruit in the Disk/Planet Orchard. GL 503.2B GL577B/C CD -33° 7795B TWA6B ? HR 7329B

Anomaly or Bias? A Jovian > 140 AU? RV Surveys suggest ~ 5% MS * s have 0.8—8 Mjup d < 3AU from their primaries. NOT Where Giant Planets are found in our own Solar System WHY ARE THEY THERE? Posited*: Mutual interactions within a disk can perturb one young planet to move into a < 1AU eccentric orbit (as inferred from RV surveys), and the other… Ejected (but bound) to very large separations, > 100AU * e,g., Lin & Ida (ApJ, 1997); Boss (2001, IAU Symp 202)

GLENN SCHNEIDER NICMOS Project Steward Observatory 933 N. Cherry Avenue University of Arizona Tucson, Arizona Phone: FAX: UV/Optical imaging and spectroscopy of collisionally evolved circumstellar debris and co-orbital bodies will play a pivotal role in furthering our understanding of the formation and evolution of exosolar planetary systems. To study physical processes acting over sub-AU spatial scales and time scales comparable to the age of our solar system will require a 3—4 order of magnitude improvement in instrumental stray light rejection over the performance obtainable with HST.

Is it, or Isn’t It? Undetected in NICMOS 0.9  m Followup Observation I-H > 3 Marginally Detected in 6-Orbit Binned STIS G750L Spectrum Colors Consistent with 2 Mjup, 10 Myr, “Hot” Giant Planet Instrument Band Bandpass Mag NICMOS/C2 F160W 1.40— NICMOS/C2 F090M 0.80—1.00 >23.1 STIS/G750L I extract 0.81—0.99 ~25.4 STIS/G750L R extract 0.63—0.77 >27.2 If NOT a hot young planet, it must be a Highly exotic object!

Is it, or Isn’t It? Undetected in NICMOS 0.9  m Followup Observation I-H > 3 Marginally Detected in 6-Orbit Binned STIS G750L Spectrum Colors Consistent with 2 Mjup, 10 Myr, “Hot” Giant Planet* 20.1 >23.1 ~25.4 >27.2 Keck/AO Astrometric (PM) Follow-up Thus-Far Inconclusive * Sudarsky et al., 2000Spectrum from A. Burrows

Is it, or Isn’t It? A differential proper motion measure will be obtained with NICMOS. If common proper motions are confirmed we will request time for NICMOS grism spectrophotometry to obtain a near-IR spectrum >23.1 ~25.4 >27.2