Gaspard Duchêne UC Berkeley – Obs. Grenoble Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Outline  The big questions and how to answer them  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long- baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The big questions  Can we empirically constrain the process of planet formation?  What are the successive stages? What is the structural evolution of disks? Where does planet formation occur? What are the associated timescales? How do disks dissipate?  Which disks will form planets? Important to compare to exoplanets surveys Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

High-resolution techniques  Scattered light imaging Optical: HST Near-IR (1-5μm): ground-based AO Requires coronagraphy: mask central regions Enables polarization mapping Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

High-resolution techniques  Scattered light imaging Optical: HST Near-IR (1-5μm): ground-based AO Requires coronagraphy: mask central regions Enables polarization mapping  Thermal emission mapping (submm/mm/cm) SMA, PdBI, eVLA, CARMA, ATCA Enables gas mapping Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

High-resolution techniques  Scattered light imaging Optical: HST Near-IR (1-5μm): ground-based AO Requires coronagraphy: mask central regions Enables polarization mapping  Thermal emission mapping (submm/mm/cm) SMA, PdBI, eVLA, CARMA, ATCA Enables gas mapping  Explicitly excluding IR interferometry here Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Complementary approaches Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Scattered light PAH imaging Thermal imaging IR interferometry

Outline  The big questions and approaches  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long-baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Scattered light imaging Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Courtesy M. Perrin

Scattered light imaging  Image the outer disk surface Estimate disk size/inclination Probe the overall flaring geometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Burrows et al. (1996) Krist et al. (2000) TW Hya

Scattered light imaging  Image the outer disk surface Estimate disk size/inclination Probe the overall flaring geometry Probe grain size/composition Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Honda et al. (2009) Duchêne et al. (2004) GG Tau HD

Scattered light imaging  Image the outer disk surface Estimate disk size/inclination Probe the overall flaring geometry Probe grain size/composition Identify large-scale asymmetries (nature?) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Fukagawa et al. (2004) Grady et al. (2001) AB AurHD

Scattered light imaging  Polarized imaging is a key asset It alleviates the contrast problem It provides physical information that helps disentangling dust properties from disk structure Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Apai et al. (2004) Oppenheimer et al. (2008) Silber et al. (2000) GG Tau AB Aur TW Hya

Main results from scattering  Outer disks are flared, consistent with hydrostatic equilibrium (good coupling) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Main results from scattering  Outer disks are flared, consistent with hydrostatic equilibrium (good coupling)  Dust grains in the surface are not much larger than ISM a max ~ 1mm strongly excluded (a max < 10μm) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Main results from scattering  Outer disks are flared, consistent with hydrostatic equilibrium (good coupling)  Dust grains in the surface are not much larger than ISM a max ~ 1mm strongly excluded (a max < 10μm)  Departures from asymmetry are common Spiral arms, gaps, dimples… Warp, variable illumination effects Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of scattering  No view of planet-forming region Masked region: AU Requires extrapolation inwards Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of scattering  No view of planet-forming region Masked region: AU Requires extrapolation inwards  Limited sensitivity to fine-scale structure Spatial resolution: 5-10 AU Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of scattering  No view of planet-forming region Masked region: AU Requires extrapolation inwards  Limited sensitivity to fine-scale structure Spatial resolution: 5-10 AU  Ambiguous interpretation of substructures Surface density features or local H 0 features? Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of scattering  No view of planet-forming region Masked region: AU Requires extrapolation inwards  Limited sensitivity to fine-scale structure Spatial resolution: 5-10 AU  Ambiguous interpretation of substructures Surface density features or local H 0 features?  Over half of known disks are undetected! No apparent SED criterion for detectability Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Outline  The big questions and approaches  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long-baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Thermal continuum mapping Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Andrews & Williams (2007)

Thermal continuum mapping  Image the outer disk midplane Estimate disk size Estimate extent of grain growth (up to ~cm) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Kitamura et al. (2002) Natta et al. (2007)

Thermal continuum mapping  Image the outer disk midplane Estimate disk size Estimate extent of grain growth (up to ~cm) Image surface density substructures Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Piétu et al. (2005) Hughes et al. (2009) AB AurGM Aur

Thermal continuum mapping  Image the outer disk midplane Estimate disk size Estimate extent of grain growth (up to ~cm) Image surface density substructures Constrain the Σ d profile Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Andrews & Williams (2007) Kitamura et al. (2007)

Gas mapping  Map simple species in warm outer disk Enable dynamical analysis of central star Serve as basis for chemistry modeling Confirm gas/dust coupling in asymmetries Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Piétu et al. (2005) AB Aur

Main results from mm mapping  Best results from highest spatial resolution  Non-power law structure: Relatively flat overall profile Tapered-off outer region Accounts for gas/dust obs.  Quite different from MMSN!  Much like similarity solution Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Isella et al. (2009)

Main results from mm mapping  Deficit of dust emission in inner regions is an unexpectedly common occurrence  No counterpart in gas! Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Guilloteau et al. (2008) Isella et al. (2010) RY Tau HH 30

Limitations of mm mapping  Limited ability to resolve substructures Linear resolution: ≥ 30 AU Requires extrapolation inwards Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of mm mapping  Limited ability to resolve substructures Linear resolution: ≥ 30 AU Requires extrapolation inwards  Innermost region is optically thick Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of mm mapping  Limited ability to resolve substructures Linear resolution: ≥ 30 AU Requires extrapolation inwards  Innermost region is optically thick  Limited sensitivity Focus on brightest disks for high resolution Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Limitations of mm mapping  Limited ability to resolve substructures Linear resolution: ≥ 30 AU Requires extrapolation inwards  Innermost region is optically thick  Limited sensitivity Focus on brightest disks for high resolution  Model-dependent results! Not enough resolution elements for data to guide modeling (apart from peculiar cases) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Outline  The big questions and approaches  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long-baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Some more ‘exotic’ datasets  PAH imaging around Herbig Ae stars Geometry of illuminated outer disk Poorer angular resolution (λ=3-11μm) A proxy to scattering, less contrast-limited Gaspard Duchêne - Circumstellar disks and planets - Kiel - May HD PDS 144N Lagage et al. (2006) Perrin et al. (2006)

Some more ‘exotic’ datasets  Spectro-astrometry of hot gas Can reach ~1mas resolution CO detected in most disks!  Gas found within inner holes  Enables dynamical studies Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Pontoppidan et al. (2008)

Some more ‘exotic’ datasets  Time domain: periodic occultation Can probe all the way to the inner radius Warp/wall in innermost disk Can probe long-term dynamics  Occurrence rate: ~30% !? Gaspard Duchêne - Circumstellar disks and planets - Kiel - May Bouvier et al. (1999, 2007) P=8.2d

Outline  The big questions and approaches  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long-baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

How about the inner disk??  The formation zone of most known exoplanets is believed to be <10 AU  What is the structure of disks on that scale?  How do the inner and outer disk relate to each other? How bad are the current extrapolations?  What is the link between planet formation and disk dissipation? Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

How about the inner disk??  Some predictions/hypotheses to be tested: Accretion geometry on central star/binary Puffed-up rim and associated shadowed region Gas within the inner rim Planet-induced gaps Snow line with pile-up of larger grains/bodies Empty (?) holes in transition disks Role of inner disk for undetected outer disks Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

How about the inner disk??  Some predictions/hypotheses to be tested: Accretion geometry on central star/binary Puffed-up rim and associated shadowed region Gas within the inner rim Planet-induced gaps Snow line with pile-up of larger grains/bodies Empty (?) holes in transition disks Role of inner disk for undetected outer disks  We need to image the inner disk Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Outline  The big questions and approaches  Scattered light imaging  (sub)mm interferometric mapping  A few ‘exotic’ approaches  Questions still to be solved  Future instrumentation and the role of long-baseline interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Future instrumentation  Next Generation AO on 8-10m telescopes NICI, SPHERE, GPI, HiCIAO, … Same resolution, much higher contrast Limited to the brightest young stars Region within AU still blocked out Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Future instrumentation  Next Generation AO on 8-10m telescopes NICI, SPHERE, GPI, HiCIAO, … Same resolution, much higher contrast Limited to the brightest young stars Region within AU still blocked out  AO on 30-40m telescopes (E-ELT, TMT, …) Higher resolution (~2 AU) Uncertain image quality Planet-forming region still out of view (?) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Future instrumentation  ALMA Much higher spatial resolution (~0.5 AU) Much improved image fidelity Innermost regions optically thick, especially at the shortest wavelengths (best resolution) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

Future instrumentation  ALMA Much higher spatial resolution (~0.5 AU) Much improved image fidelity Innermost regions optically thick, especially at the shortest wavelengths (best resolution)  JWST PSF stability enables HST-like work in the mid-IR Probe of 1-10μm dust grains (rarely doable now) Limited spatial resolution (~40 AU) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The realm of interferometry  For most disks: 0.15 AU ≅ 0.001” Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The realm of interferometry  For most disks: 0.15 AU ≅ 0.001”  Large number of baseline critical  Many beams across the image needed We need empirically-based input to improve our general understanding and detailed modeling Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The realm of interferometry  For most disks: 0.15 AU ≅ 0.001”  Large number of baseline critical  Many beams across the image needed We need empirically-based input to improve our general understanding and detailed modeling  Large dynamical range required Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The realm of interferometry  For most disks: 0.15 AU ≅ 0.001”  Large number of baseline critical  Many beams across the image needed We need empirically-based input to improve our general understanding and detailed modeling  Large dynamical range required  Sensitivity key to survey broad samples Gaspard Duchêne - Circumstellar disks and planets - Kiel - May

The realm of interferometry  For most disks: 0.15 AU ≅ 0.001”  Large number of baseline critical  Many beams across the image needed We need empirically-based input to improve our general understanding and detailed modeling  Large dynamical range required  Sensitivity key to survey broad samples  Inner disk midplane is out of reach! Optically thick at all wavelengths Gaspard Duchêne - Circumstellar disks and planets - Kiel - May