Mariana Orellana, Lucas. A. Cieza, M. R. Schreiber, B. Merin, J. M. Brown, L. J. Pellizza, Gisela A. Romero
A large set of Spitzer-selected transitional disks in the Ophiuchus molecular
cloud was recently examined by Cieza et al (2010), and 4 of the targets were
identified as (giant) planet-forming candidates based on the morphology of
their Spectral Energy Distributions (SEDs), the apparent lack of stellar
companions, and evidence for accretion. Here we characterize the structures of
these disks modeling their optical, infrared and (sub)millimeter SEDs. We use
the Monte Carlo radiative transfer package RADMC to construct a parametric
model of the dust distribution in a flared disk with an inner cavity and
calculate the temperature structure consistent with the density profile, in
thermal equilibrium with the irradiating star. For each object, we conducted a
Bayesian exploration of the parameter space generating Monte Carlo Markov
Chains (MCMC) that allow the identification of the best fit parameters and to
constrain their range of statistical confidence. Our calculations point to the
presence of evacuated cavities with radii ~2-8 AU, consistent with having been
carved by embedded giant planets. We found parameter values consistent with
those previously given in the literature, indicating a mild degree of grain
growth and dust settling, which deserves to be investigated with further
modeling and follow up observations. Resolved images with (sub)millimeter
interferometers are required to break some of the degeneracies of the models
and better constrain the physical properties of these fascinating disks.
View original:
http://arxiv.org/abs/1111.5499
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