Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations

Astronomy & Astrophysics, Jul 2014

Context. Constraining the gas and dust disk structure of transition disks, particularly in the inner dust cavity, is a crucial step toward understanding the link between them and planet formation. HD 135344B is an accreting (pre-)transition disk that displays the CO 4.7 μm emission extending tens of AU inside its 30 AU dust cavity. Aims. We constrain HD 135344B’s disk structure from multi-instrument gas and dust observations.Methods. We used the dust radiative transfer code MCFOST and the thermochemical code ProDiMo to derive the disk structure from the simultaneous modeling of the spectral energy distribution (SED), VLT/CRIRES CO P(10) 4.75 μm, Herschel/PACS [O i] 63 μm, Spitzer/IRS, and JCMT 12CO J = 3−2 spectra, VLTI/PIONIER H-band visibilities, and constraints from (sub-)mm continuum interferometry and near-IR imaging. Results. We found a disk model able to describe the current gas and dust observations simultaneously. This disk has the following structure. (1) To simultaneously reproduce the SED, the near-IR interferometry data, and the CO ro-vibrational emission, refractory grains (we suggest carbon) are present inside the silicate sublimation radius (0.08 <R< 0.2 AU). (2) The dust cavity (R< 30 AU) is filled with gas, the surface density of the gas inside the cavity must increase with radius to fit the CO ro-vibrational line profile, a small gap of a few AU in the gas distribution is compatible with current data, and a large gap of tens of AU in the gas does not appear likely. (4) The gas-to-dust ratio inside the cavity is >100 to account for the 870 μm continuum upper limit and the CO P(10) line flux. (5) The gas-to-dust ratio in the outer disk (30 <R< 200 AU) is <10 to simultaneously describe the [O i] 63 μm line flux and the CO P(10) line profile. (6) In the outer disk, most of the gas and dust mass should be located in the midplane, and a significant fraction of the dust should be in large grains. Conclusions. Simultaneous modeling of the gas and dust is required to break the model degeneracies and constrain the disk structure. An increasing gas surface density with radius in the inner cavity echoes the effect of a migrating jovian planet in the disk structure. The low gas mass (a few Jupiter masses) throughout the HD 135344B disk supports the idea that it is an evolved disk that has already lost a large portion of its mass.

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Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations

A&A Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength ?;??;??? gas and dust observations A. Carmona 3 C. Pinte 1 3 W. F. Thi 3 M. Benisty 3 F. Ménard 1 3 C. Grady 0 6 7 I. Kamp 5 P. Woitke 4 J. Olofsson 9 A. Roberge 6 S. Brittain 8 G. Duchêne 2 3 G. Meeus 11 C. Martin-Zaïdi 3 B. Dent 12 J. B. Le Bouquin 3 J. P. Berger 3 10 0 Eureka Scientific , 2452 Delmer, Suite 100, Oakland CA 96002 , USA 1 UMI-FCA, CNRS/INSU France (UMI 3386), and Departamento de Astronomía, Universidad de Chile , 36D Casila, Santiago , Chile 2 Astronomy Department, University of California , Berkeley CA 94720-3411 , USA 3 UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) UMR 5274 , 38041 Grenoble , France 4 SUPA, School of Physics and Astronomy, University of St Andrews , St Andrews KY16 9SS , UK 5 Kapteyn Astronomical Institute , PO Box 800, 9700 AV Groningen , The Netherlands 6 Goddard Center for Astrobiology, Goddard Space Flight Center , Greenbelt MD 20771 , USA 7 ExoPlanets and Stellar Astrophysics Laboratory , Code 667 , Goddard Space Flight Center , Greenbelt MD 20771 , USA 8 Department of Physics & Astronomy, 118 Kinard Laboratory, Clemson University , Clemson SC 29634 , USA 9 Max Planck Institut für Astronomie , Königstuhl 17, 69117 Heidelberg , Germany 10 European Southern Observatory, Alonso de Córdova , 3107 Vitacura , Chile 11 Departamento de Física Teórica, Universidad Autonoma de Madrid , Campus Cantoblanco, 28049 Madrid , Spain 12 Joint ALMA Observatory , Alonso de Córdova 3107, 763-0355 Vitacura, Santiago , Chile Context. Constraining the gas and dust disk structure of transition disks, particularly in the inner dust cavity, is a crucial step toward understanding the link between them and planet formation. HD 135344B is an accreting (pre-)transition disk that displays the CO 4.7 m emission extending tens of AU inside its 30 AU dust cavity. Aims. We constrain HD 135344B's disk structure from multi-instrument gas and dust observations. Methods. We used the dust radiative transfer code MCFOST and the thermochemical code ProDiMo to derive the disk structure from the simultaneous modeling of the spectral energy distribution (SED), VLT/CRIRES CO P(10) 4.75 m, Herschel/PACS [O i] 63 m, Spitzer/IRS, and JCMT 12CO J = 3 2 spectra, VLTI/PIONIER H-band visibilities, and constraints from (sub-)mm continuum interferometry and near-IR imaging. Results. We found a disk model able to describe the current gas and dust observations simultaneously. This disk has the following structure. (1) To simultaneously reproduce the SED, the near-IR interferometry data, and the CO ro-vibrational emission, refractory grains (we suggest carbon) are present inside the silicate sublimation radius (0:08 < R < 0:2 AU). (2) The dust cavity (R < 30 AU) is filled with gas, the surface density of the gas inside the cavity must increase with radius to fit the CO ro-vibrational line profile, a small gap of a few AU in the gas distribution is compatible with current data, and a large gap of tens of AU in the gas does not appear likely. (4) The gas-to-dust ratio inside the cavity is >100 to account for the 870 m continuum upper limit and the CO P(10) line flux. (5) The gas-to-dust ratio in the outer disk (30 < R < 200 AU) is <10 to simultaneously describe the [O i] 63 m line flux and the CO P(10) line profile. (6) In the outer disk, most of the gas and dust mass should be located in the midplane, and a significant fraction of the dust should be in large grains. Conclusions. Simultaneous modeling of the gas and dust is required to break the model degeneracies and constrain the disk structure. An increasing gas surface density with radius in the inner cavity echoes the e ect of a migrating jovian planet in the disk structure. The low gas mass (a few Jupiter masses) throughout the HD 135344B disk supports the idea that it is an evolved disk that has already lost a large portion of its mass. protoplanetary disks - stars; pre-main sequence - planets and satellites; formation - techniques; high angular resolution - techniques; interferometric - stars; individual; HD 135344B (SAO 206462) - ? Based on PIONIER, CRIRES, and UVES observations collected at the VLTI and VLT (European Southern Observatory, Paranal, Chile) with programs 087.C-0702(A,B,D), 087.C-0458(C), 087.C-0703(B), 179.C-0151(A), 077.C-0521(A). ?? Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. ??? Appendix A is available in electronic form at http://www.aanda.org 1. Introduction Observations of young stars of di erent ages reveal that protoplanetary disks evolve from optically thick, gas-rich disks to optically thin, gas-poor debris disks (e.g., see review by Williams & Cieza 2011) . The transition between these two classes of objects is believed to occur relatively fast (...truncated)


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A. Carmona, C. Pinte, W. F. Thi, M. Benisty, F. Ménard, C. Grady, I. Kamp, P. Woitke, J. Olofsson, A. Roberge, S. Brittain, G. Duchêne, G. Meeus, C. Martin-Zaïdi, B. Dent, J. B. Le Bouquin, J. P. Berger. Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations, Astronomy & Astrophysics, 2014, pp. A51, 567, DOI: 10.1051/0004-6361/201322534