Formation et évolution des systèmes planétaires – DiskEvol

The research program is organised in 3 main tasks :
Task 1: Database of observations and models for the GASPS project The goal is to provide complementary data in the millimeter regions for the GASPS source and to make this data quickly available within the consortium. The second objective is to build tools that will allow detailed interpretation of these data sets. We will compute a grid of radiative transfer models with MCFOST (SEDs and line fluxes for the lines observed by GASPS) over a wide range of spectral types and disk parameters. The ultimate objective of this first task is to build a uniform and easy-to- access set of data (observations and models) that will be intensively used for interpretation.
Task 2: Analysis of the GASPS results: a dust and gas inventory of disks We will interpret the observed signatures of both the dust and gas with respect to the aforementioned grid of models. The statistical comparison of the grid of models with the observational data sets will offer us the ability to interpret observational trends in terms of model parameters. We will search for the most direct signatures of disk evolution: inner hole size, gas mass and chemical state, dust growth and settling in order to estimate the timescales for evolution and set constraints on the processes at work.
Task 3: A complete view of the dust structure and gas chemistry in disks To characterise the processes by which disks evolve, the statistical results of task 2 must be completed by model fitting of a selected sample of representative sources, which will serve as references for the global analysis. We will precisely analyse CO molecular maps of this selected sample of disks. This will allow us to constrain the kinematics and dynamics of the gas, to measure the gas scale height and temperature and compare them to the dust ones, as well as analyse water molecule lines to constrain the physical conditions of the molecular gas in the planet forming region of protoplanetary disks.

Progress has been on all aspects of the project and accordingly to
the initial plan. 28 refereed publications have resulted from this work so far.

Task 1 :
- the anciallary data sets from IRAM have been reduced and published (Mathews et al 2012).
- A new collaboration on the analysis and publication of Herschel data on a sample of brown dwarfs (Harvey et al 2011, 2012) has been initiated.
- A new program to detect edge-on disk with HST has been initiated, resulting in 8 discoveries
- The program to collect interferometric data with PIONIER has started as well as its analysis with complementary data, for instance from Herschel DIGIT.


Task 2 :
- New modelling tools have been set up to compare the observational data with models in a very efficient way (parallel genetic and MCMC algorithms which have been tailored to the problem).
- Study of the results of the DENT grid : establishing diagnostics for the gaz in disks.
- Modelling of the SEDs of the Taurus objects (Pinte et al, in prep.) and
Upper Sco.
- The analysis of the statististical results of GASPS has led to several
publications : for Herbig Ae stars (Meeus et al 2012), the detection of water in the disks in Taurus (Riviere et al 2012), the comparison of the emission from disks and jets (Podio et al 2012), the detection of CH+ around HD 100546 (Thi et al 2011).

Task 3 :
- Detailed modelling of the disks surounding TW Hydra, HD163296,
HK Tau, T Cha, HD 100546, HD 181327, HD 172555/
- Developping the tools to study the CO ro-vibrational lines (HD135344 B, Carmona et al 2013).
- Studying the effect of the water chenistry and of the details of radiative transfer on water emission lines (Kamp et al 2013)
- Interfacing the mcfost code with the LIDT code from CEA/Saclay (S. Charnoz) and phantom code (D. Price, G. laibe) to study the evolution of dust grains in disks.

The studies developped in DIskEvol will become more influential with the advent of the ALMA interferometer and JWST space telescopes, that will complement Herschel observations at both longer and shorter wavelengths. ALMA is providing images and velocity maps at high spatial resolution (and not only integrated quantities as in the case of Herschel). It probes the density, temperature and abundance gradients non only in the external parts of disks but also closer to the star, at spatial scales of the order of 10 AU. Er are now at a point where we can predict, using the aforementioned RT / chemistry codes (MCFOST and ProDiMo), the emission maps (continuum and molecular lines), as they will be seen by ALMA, and to determine the spatial dependence of the physico-chemical conditions. JWST’s imaging and spectroscopy capabilities will complement Herschel observations at shorter wavelengths, and in particular will determine more precisely than Spitzer the constituents of the dust grains, it will observed the highly excited hot CO (ro-vibrational bands around 2.3 and 4.6 µm) in the central regions of the disks, and will study organic molecules that are important for life to develop.

In particular, the GASPS sources, for which we will have detailed models, are very likely to be priority targets for ALMA and JWST. We will use the results of the aforementioned tasks to make predictions regarding the observable consequences of gas and dust evolution, and planet formation. These aspects are key drivers for both instruments and our calculations will provide the best estimates, closest to reality, for signatures of evolution in disks.

Howard et al., 2013, ApJ, 776, 21
Mathews, Pinte, Duchene, Williams, and Menard, 2013, A&A, 558, A66
de Gregorio-Monsalvo et al., 2013, A&A, 557, A133
Thi et al., 2013, A&A, 557, A111
Canovas et al., 2013, A&A, 556, A123
Riviere-Marichalar et al., 2013, A&A, 555, A67
Dent et al., 2013, PASP, 125, 477
Olofsson et al., 2013, A&A, 552, A4
Podio et al., 2013, ApJl, 766, L5
Cieza et al., 2013, ApJ, 762, 100
Gonzalez, Pinte, Maddison, Menard, and Fouchet, 2012, A&A, 547, A58
Riviere-Marichalar et al., 2012, A&A, 546, L8
Podio et al., 2012, A&A, 545, A44
Harvey et al., 2012, ApJ, 755, 67
Meeus et al., 2012, A&A, 544, A78
Lebreton et al., 2012, A&A, 539, A17
Riviere-Marichalar et al., 2012, A&A, 538, L3
Tilling et al., 2012, A&A, 538, A20
Mathews et al., 2012, ApJ, 745, 23
Harvey et al., 2012, ApJl, 744, L1
Cieza et al., 2011, ApJl, 741, L25
Melis et al., 2011, ApJl, 739, L7
Kamp et al., 2011, A&A, 532, A85
Patience et al., 2011, A&A, 531, L17
Tatulli et al., 2011, A&A, 531, A1
Thi et al., 2011, A&A, 530, L2
Olofsson et al., 2011, A&A, 528, L6
McCabe et al., 2011, ApJ, 727, 90