21 Mars 2006Visions for infrared astronomy1 Protoplanetary worlds at the AU scale Jean Philippe Berger J. Monnier, R. Millan-Gabet, W. Traub, M. Benisty, F. Malbet, E. Pedretti

21 Mars 2006Visions for infrared astronomy2 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 2006Visions for infrared astronomy3 A young star’s environment Presence of a flared disk of gas and dust associated with bipolar mass loss: winds and/or highly collimated jets, Typical disk sizes: AU. Infrared excess Optical(HubbleAO) /mm imaging

21 Mars 2006Visions for infrared astronomy4 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 2006Visions for infrared astronomy5 Tuthill, Monnier & Danchi 2001 Optically Thin Cavity Optically Thick, Geometrically Thin Disk 2001: important revision of the model Dullemond et al Natta, 2001

21 Mars 2006Visions for infrared astronomy6 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. Eisner, 2004

21 Mars 2006Visions for infrared astronomy7 2T interferometry: the near-IR view

21 Mars 2006Visions for infrared astronomy8 2T interferometry: the near-IR view TTauris 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 2006Visions for infrared astronomy9 2T interferometry: the near-IR view 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

21 Mars 2006Visions for infrared astronomy10 2T interferometry: the near-IR view Presence of resolved Flux (halo, envelop renmant) IntrinsicVariability Visibility modelling is highly sensitive To the knowledge of short baseline incohernet Flux and stellar vs. disk emission ratio

21 Mars 2006Visions for infrared astronomy11 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 2006Visions for infrared astronomy12 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. Isella et al 2005

21 Mars 2006Visions for infrared astronomy13 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 2006Visions for infrared astronomy14

21 Mars 2006Visions for infrared astronomy15 Results  Essentially zero closure phases  Evidence for resolved flux (incoherent)?

21 Mars 2006Visions for infrared astronomy16 Interpretation in the inner rim context

21 Mars 2006Visions for infrared astronomy17 Interpretation in the inner rim context

21 Mars 2006Visions for infrared astronomy18 Parametric imaging

21 Mars 2006Visions for infrared astronomy19 Direct imaging Berger et al, 2006 Image reconstruction: Meimon, Mugnier, ONERA

21 Mars 2006Visions for infrared astronomy20 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. H K 260 m baseline! K Klahr & Kley (2005, A&A in press) Hot accreting planets in disks? Micro-jets