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High-resolution disks Observations

Gaspard Duchêne UC Berkeley – Obs. Grenoble. High-resolution disks Observations. 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

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High-resolution disks Observations

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  1. Gaspard Duchêne UC Berkeley – Obs. Grenoble High-resolution disks Observations Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  2. Outline • The big questions and how to answer them • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  3. 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 26-28 2010

  4. 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 26-28 2010

  5. 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 26-28 2010

  6. 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 interferometryhere Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  7. Complementary approaches PAH imaging Scattered light Thermal imaging IR interferometry Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  8. Outline • The big questions and approaches • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  9. Scattered light imaging Courtesy M. Perrin Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  10. Scattered light imaging • Image the outer disk surface • Estimate disk size/inclination • Probe the overall flaring geometry TW Hya Burrows et al. (1996) Krist et al. (2000) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  11. Scattered light imaging • Image the outer disk surface • Estimate disk size/inclination • Probe the overall flaring geometry • Probe grain size/composition Honda et al. (2009) GG Tau HD 142527 Duchêne et al. (2004) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  12. 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?) AB Aur HD 100546 Fukagawa et al. (2004) Grady et al. (2001) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  13. 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 GG Tau AB Aur TW Hya Silber et al. (2000) Apai et al. (2004) Oppenheimer et al. (2008) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  14. Main results from scattering • Outer disks are flared, consistent with hydrostatic equilibrium (good coupling) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  15. 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 • amax ~ 1mm strongly excluded (amax < 10μm) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  16. 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 • amax ~ 1mm strongly excluded (amax < 10μm) • Departures from asymmetry are common • Spiral arms, gaps, dimples… • Warp, variable illumination effects Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  17. Limitations of scattering • No view of planet-forming region • Masked region: 40-100 AU • Requires extrapolation inwards Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  18. Limitations of scattering • No view of planet-forming region • Masked region: 40-100 AU • Requires extrapolation inwards • Limited sensitivity to fine-scale structure • Spatial resolution: 5-10 AU Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  19. Limitations of scattering • No view of planet-forming region • Masked region: 40-100 AU • Requires extrapolation inwards • Limited sensitivity to fine-scale structure • Spatial resolution: 5-10 AU • Ambiguous interpretation of substructures • Surface density features or local H0 features? Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  20. Limitations of scattering • No view of planet-forming region • Masked region: 40-100 AU • Requires extrapolation inwards • Limited sensitivity to fine-scale structure • Spatial resolution: 5-10 AU • Ambiguous interpretation of substructures • Surface density features or local H0 features? • Over half of known disks are undetected! • No apparent SED criterion for detectability Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  21. Outline • The big questions and approaches • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  22. Thermal continuum mapping Andrews & Williams (2007) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  23. Thermal continuum mapping • Image the outer disk midplane • Estimate disk size • Estimate extent of grain growth (up to ~cm) Natta et al. (2007) Kitamura et al. (2002) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  24. Thermal continuum mapping • Image the outer disk midplane • Estimate disk size • Estimate extent of grain growth (up to ~cm) • Image surface density substructures AB Aur GM Aur Piétu et al. (2005) Hughes et al. (2009) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  25. 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 Σd profile Andrews & Williams (2007) Kitamura et al. (2007) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  26. 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 AB Aur Piétu et al. (2005) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  27. 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 Isella et al. (2009) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  28. Main results from mm mapping • Deficit of dust emission in inner regions is an unexpectedly common occurrence • No counterpart in gas! HH 30 RY Tau Isella et al. (2010) Guilloteau et al. (2008) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  29. Limitations of mm mapping • Limited ability to resolve substructures • Linear resolution: ≥ 30 AU • Requires extrapolation inwards Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  30. 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 26-28 2010

  31. 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 26-28 2010

  32. 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 26-28 2010

  33. Outline • The big questions and approaches • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  34. Some more ‘exotic’ datasets • PAH imaging around HerbigAe stars • Geometry of illuminated outer disk • Poorer angular resolution (λ=3-11μm) • A proxy to scattering, less contrast-limited PDS 144N HD 97048 Lagage et al. (2006) Perrin et al. (2006) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  35. 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 Pontoppidan et al. (2008) Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  36. 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% !? Bouvier et al. (1999, 2007) P=8.2d Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  37. Outline • The big questions and approaches • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  38. 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 26-28 2010

  39. How about the inner disk?? • Some predictions/hypothesesto 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 26-28 2010

  40. How about the inner disk?? • Some predictions/hypothesesto 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 26-28 2010

  41. Outline • The big questions and approaches • Scattered light imaging • (sub)mminterferometric 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 26-28 2010

  42. 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 10-20 AU still blocked out Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  43. 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 10-20 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 26-28 2010

  44. 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 26-28 2010

  45. 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 26-28 2010

  46. The realm of interferometry • For most disks: 0.15 AU ≅ 0.001” Gaspard Duchêne - Circumstellar disks and planets - Kiel - May 26-28 2010

  47. 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 26-28 2010

  48. 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 26-28 2010

  49. 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 26-28 2010

  50. 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 26-28 2010

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