High Angular Resolution Studies of the Structure of Protoplanetary Disks Surrounding IntermediateMas

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High Angular Resolution Studies of the Structure
of Protoplanetary Disks Surrounding
Intermediate-Mass Stars

• Mario van den Ancker ESO Garching

Collaborators Davide Fedele (MPIA Heidelberg),
Gerrit van der Plas (ESO/Univ. Amsterdam), Bram
Acke (KU Leuven), Jeroen Bouwman (MPIA
Heidelberg), Rens Waters (Univ. Amsterdam),
Markus Wittkowski (ESO)
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Herbig Ae/Be Stars A Primer

• Young (lt 10 Myr) intermediate-mass (2-10 solar
  mass) stars surrounded by protoplanetary disks
• Observationally advantageous targets as disks are
  brighter and more extended than around T Tauri
  stars
• About 200 known in our galaxy

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Meeus et al. (2001) Classification Scheme Herbig
Ae/Be Stars
Group I
Group II
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Correlations with Meeus et al. classification
scheme
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A Comparison of the Distribution of Gas and Dust
in Protoplanetary Disks

• Poorly constrained observationally
• Two tracers sensitive to the 1-10 AU region for
  systems at 100-200 pc
• Gas O I 6300 Å emission line
• Dust Mid-IR (8-13 µm) Interferometry

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O I Emission VLT/UVES Observations
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O I emission Non-thermal
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O I emission Due to photo-dissociation of OH
by stellar UV photons in upper layers flared disk
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HD 179218 Group I Flared Disk
HD 101412 Group II Self-shadowed Disk
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VLTI/MIDI Observations (I)
HD 179218 (group I flared disk)
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VLTI/MIDI Observations (II)
HD 101412 (group II self-shadowed disk)
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Conclusions

• HD 179218 Dust seen further out than O I
  emission little OH in surface layers past 15 AU?
• HD 101412 Scale height of gas larger than dust
  disk self-shadowed in dust, but not in gas!
• Evolution from flared disks to self-shadowed
  disks
• Driver loss of gas-dust coupling in disk
  atmosphere?