Max Planck Institute for Astronomy - Annual Report 2005

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70 III. Scientific Work Column density (arbitrary units) 60 60 50 50 40 40 Pixel 30 30 20 20 10 10 0 0 0 0 10 Fig. III.2.7: Simulated 10 µm images of the inner region (radius 20 AU) of a circumstellar T-Tauri disk, with an embedded Jupiter-mass planet at a distance of 5.2 AU from the central star (Wolf and Klahr 2005). The left image shows the disk under an inclination of 0°, the right under 60°. For both inclinations, the hot region around the planet above the center of the disk, indicated as bright areas in these reemission images, is clearly visible. Assuming a distance of 140 pc, the corresponding 20 mas scale is indicated in the lower right edge of both images. 20 30 Pixel 40 50 60 10 20 30 40 50 60 Fig. III.2.6: Simulated scattered light image of a debris disk with an embedded planet (Jupiter-mass planet; orbital radius: 54 AU; dust grain radius: 9 µm). 2.8 AU 20 m� @ 140 pc (depending on the observing wavelength and AT/UT configuration), MatIssE will be the ideal instrument to study the planet-forming region in circumstellar disks. Two exemplary questions which MatIssE will be able to address are the following: [1] Is the inner disk structure modified by early stages of planet formation? – The inner region of circumstellar disks is expected (but not yet proven) to show large-scale (sub-AU to AU sized) density fluctuations and inhomogenities. The most prominent examples are predicted long-lived anti-cyclonic vortices in which an increased density of dust grains may undergo an accelerated growth process – the first step towards planet formation (Klahr and Bodenheimer 2003). Locally increased densities and the resulting locally increased disk scale height have direct impact on the heating of the disk by the central star and are expected to show up as local brightness variations (due to increased absorption or shadowing effects) in the midinfrared images (for illustration, see Fig. III.2.7). [2] What is the status of disk clearing within the inner few AU? – According to the temperature and luminosity of the central star, the sublimation radius for dust grains is in the order of 0.1 – 1 AU (T-Tauri and Herbig Ae/Be stars). This can be approximately spatially resolved with MatIssE in the L band in the case of nearby YSOs. However, in contrast to these values, an even significantly larger inner dust disk radius of about 4 AU has been deduced from SED modelling in the 10 Myr old protoplanetary disk around TW Hydrae (Calvet et al. 2002). Other examples are the object CoKu Tau/4 with an evacuated inner zone of radius � 10 AU (D'Alessio et al. 2005, Quillen et al. 2004) and GM Aur with a significant decrease of the dust reemission inside about 4 AU around the central star (Rice et al. 2003). This gap is characterized by a depletion of at least the population of small dust grains which are responsible for the near- to mid-infrared flux. The confirmation of these indirectly determined gaps, 2.8 AU 20 m� @ 140 pc
0.05 � Fig. III.2.8: Simulated 10 µm image of the inner region of a T-Tauri circumstellar disk with a cleared inner region, seen under an inclination of 60° (assumed distance: 140 pc). Left: original image, convolved with a PSF corresponding to a 202 as well as the test of other disks for the existence of similar gaps will provide valuable constraints on the evolution of the planet-forming region and thus on the process of planet formation itself (see Fig. III.2.8 for an illustration of the feasibility to detect a large inner gap with MatIssE). The radiative transfer simulations which Figures III.2.7 and III.2.8 have been performed with the radiative transfer code MC3D, a 3D continuum radiative transfer code which combines the most recent Monte Carlo radiative transfer concepts for both the self-consistent radiative transfer, i.e., the estimation of spatial dust temperature distributions, and pure scattering applications, taking into account the polarization state of the radiation field (Wolf 2003). The code is available for download at www.mpia. de/homes/swolf/mc3d-public/mc3d-public.html. Future Prospects The perspective of applying the inverse 3D radiative transfer method to other cores is promising. Every additional image observed at other wavelengths will introduce new constraints for the unknown parameter, and will thus increase the accuracy of the determined density structure. The ultimate goal of applying the method to well-observed cores, however, will be to address the key question of early star formation, namely if the considered cores have in-falling material. The current line observations provide the molecular line emission flux integrated over all moving gas cells along the line of sight. III.2 Radiative Transfer – Link between Simulation and Observation 71 m aperture. Right: Reconstructed image. Configuration: seven nights of observing time with three axilliary telescopes (ATs) on Paranal. (MatIssE Science case study) In the general case, gas motion and emissivity of the cells can not be disentangled, and the 1D approximation or shearing layers are assumed to unfold it. Without unfolding it, infall motion can be mixed up with rotational motion leaving it undecided if the core shows any sign for the onset of star formation. This is changed if the core has been investigated with the new method. Knowing the full 3D structure in dust density and temperature, the line of sight-integral can be inverted providing the complete kinematical information if the considered line is optically thin and a model for the depletion of the considered molecules is used. This direct verification of infall motion would also allow to answer the question if the infall occurs spherically or through a first phase accretion disk. (Jürgen Steinacker, Sebastian Wolf, Hubert Klahr, Cornelis Dullemond, Yaroslav Pavlyuchenkov, Thomas Henning, Manfred Stickel, In collaboration with colleagues from Observatoire de Bordeaux, Astrophysikalisches Institut Potsdam, Institut für Astronomie und Astrophysik der Universität Tübingen, Steward Observatory of the University of Arizona, Department of Planetary Sciences of the University of Arizona and California Institute of Technology)
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Max Planck Institute for Astronomy
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Max Planck Institute for Astronomy
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Contents Preface ..................
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6 I. General I.1 Scientific Goals U
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8 I. General massive protostars and
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10 I. General achieve higher angula
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12 I. General The institute is co-l
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14 I. General Point Source sensitiv
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16 I. General Edinburgh Groningen D
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18 II. Highlights II.1 Light Echoes
Page 22 and 23: 20 II. Highlights 10 arcsec Fig. II
Page 24 and 25: 22 II. Highlights AB Dor C AB Dor A
Page 26 and 27: 24 II. Highlights II.3 The First He
Page 28 and 29: 26 II. Highlights II.4 Planetesimal
Page 30 and 31: 28 II. Highlights azimuthal directi
Page 32 and 33: 30 II. Highlights ticles fall faste
Page 34 and 35: 32 II. Highlights ANTU Seyfert 2 ga
Page 36 and 37: 34 II. Highlights cretion disk, one
Page 38 and 39: 36 II. Highlights 8.5 �m 2.3 ly 0
Page 40 and 41: 38 II. Highlights II.6 Massive Star
Page 42 and 43: 40 II. Highlights log M� /pc2 �
Page 44 and 45: 42 II. Highlights II.7 Observations
Page 46 and 47: 44 II. Highlights log IR luminosity
Page 48 and 49: 46 II.8 Dynamics, Dust, and Young S
Page 50 and 51: 48 II. Highlights and we see a temp
Page 52 and 53: 50 III. Selected Research Areas III
Page 54 and 55: 52 III. Scientific Work Fig. III.1.
Page 56 and 57: 54 III. Scientific Work the Data Ar
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Page 74 and 75: 72 III.3 The Galaxy-Dark Matter Con
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Page 80 and 81: 78 III. Scientific Work tion rate o
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Page 84 and 85: 82 III. Scientific Work DDO 53 HO I
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Page 90 and 91: 88 IV. Instrumental Development All
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Page 112 and 113: 110 V. People and Events 1� 10�
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120 V. People and Events Fig. V.5.2
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124 V. People and Events These oppo
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130 V. People and Events V.10 The P
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132 V. People and Events Abb. V.11.
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134 V. People and Events V.13 Four
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136 V. People and Events Lemke: I w
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138 V. People and Events Fig. V.13.
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140 V. People and Events V.14 Where
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142 V. People and Events against sp
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144 Staff Directors: Henning (Actin
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146 Working Groups Rainer Lenzen, H
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148 Cooperation with industrial Fir
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150 Conferences Conferences and Mee
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152 Conferences D. Lemke: JWST-miri
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154 Conferences/Service in Comitees
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156 Publications Szalay, I. Szapudi
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158 Publications Hamilton, C. M., W
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160 Publications Brinkmann, D. G. Y
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162 Publications Zheng, X. Z., F. H
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164 Publications of the wheel mecha
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166 Publications ASP Conf. Ser. 331
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The Max Planck Society The Max Plan
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Max Planck Institute for Astronomy - Annual Report 2005

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