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21 Mars 2006 Visions for infrared astronomy 1
Protoplanetary worlds at the AU scale
Jean Philippe BergerJ. Monnier, R. Millan-Gabet, W. Traub, M. Benisty, F.
Malbet, E. Pedretti
21 Mars 2006 Visions for infrared astronomy 2
Outline
A young star’s environment The contribution of two telescope
broadband infrared interferometry to the knowledge of disk structure
First steps towards imaging Conclusion
21 Mars 2006 Visions for infrared astronomy 3
A young star’s environment
Presence of a flared disk of gas and dust associated with bipolarmass loss: winds and/or highly collimated jets, Typical disk sizes: 50-1000AU.
Infrared excess
Optical(HubbleAO)/mm imaging
21 Mars 2006 Visions for infrared astronomy 4
The standard disk model
• Optically thick disk both for inner gas and outer dust
• Simple power-law temperature distribution (T r-0.75, T r-0.5)
• Oblique disk heating
-> fits rather well spectral energy distributions (SEDs)
e.g. Malbet & Bertout (1995, A&AS 113, 369)
21 Mars 2006 Visions for infrared astronomy 5
Tuthill, Monnier & Danchi 2001
Optically Thin Cavity
Optically Thick, Geometrically Thin Disk
2001: important revision of the model
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Dullemond et al. 2001Natta, 2001
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2T interferometry: the near-IR view
PTI, IOTA and Keck have played a major role in near infrared YSO observing during (Malbet& Berger 98, Millan-Gabet 2001,Akeson2000,02 Eisner2002,2004, Monnier)
Authors concluded Herbig AeBe and T Tauri estimated sizes often bigger than predicted with standard disk model.
Signs for disk flattening at the astronomical unit scale.
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Eisner, 2004
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2T interferometry: the near-IR view
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2T interferometry: the near-IR view
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TTauris
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1. Evidence for inner rim (Muzerolle 2004)
2. Flared disk can account for some estimated sizes (Lachaume 2003)
3. Fu Orionis stars observations compatible with standard models provided renmant envelopes or putative companions are taken into account (Malbet 2005, Millan-Gabet 20050
21 Mars 2006 Visions for infrared astronomy 9
2T interferometry: the near-IR view
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Herbig Be Stars
1. Some visibilities observations are compatible with standard disk (Malbet, 2005)
2. Evolutionary status of these stars should be debated (Monnier 2006)
Wind
Disk Disk
21 Mars 2006 Visions for infrared astronomy 10
2T interferometry: the near-IR view
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Presence of resolvedFlux (halo, envelop renmant)
IntrinsicVariability
Visibility modelling is highly sensitiveTo the knowledge of short baseline incohernetFlux and stellar vs. disk emission ratio
21 Mars 2006 Visions for infrared astronomy 11
2T interferometry: the midIR view
Sizes consistent with flat self-shadowed / flaring disk model SED classification
Flaring
Self-shadowed
Leinert et al. (2004, A&A, 423, 537)
Sizes consistent with flat self-shadowed / flaring disk model SED classification
21 Mars 2006 Visions for infrared astronomy 12
First steps towards imaging This IONIC3/IOTA campaign
was aimed at surveying the brightest HerbigAeBe and Ttauri stars in search for any asymetry (departure from zero closure phase) at the astronomical unit scale in order to select candidates for imaging.
Both a flared disk and disk with inner rim generate asymetries.
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Isella et al 2005
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First steps towards imaging
Malbet 2001
This IONIC3/IOTA campaign was aimed at surveying the brightest HerbigAeBe and Ttauri stars in search for any asymetry (departure from zero closure phase) at the astronomical unit scale in order to select candidates for imaging.
Both a flared disk and disk with inner rim generate asymetries.
21 Mars 2006 Visions for infrared astronomy 14
21 Mars 2006 Visions for infrared astronomy 15
Results
Essentially zero closure phases
Evidence for resolved flux (incoherent)?
21 Mars 2006 Visions for infrared astronomy 16
Interpretation in the inner rim context
21 Mars 2006 Visions for infrared astronomy 17
Interpretation in the inner rim context
21 Mars 2006 Visions for infrared astronomy 18
Parametric imaging
21 Mars 2006 Visions for infrared astronomy 19
Direct imaging
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Berger et al, 2006Image reconstruction:Meimon, Mugnier, ONERA
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Imaging protoplanetary disks
Imaging the inner AU requires a lot of telescopes and (preferably than) or a lot of array configurations
Model ambiguities often vanish at longer baselines
YSO short baselines images (i.e AO), are essential.
Simultaneous photometry is very important
Understanding the disk structure would ideally require joint near and mid-infrared observations
Second generation VLTI instrumentation is more than welcome.
IOTA3 @ H
CHARA @ K260 m baseline!
Keck-I @ KKlahr & Kley (2005, A&A in press)
Hot accreting planets in disks?
Micro-jets