A Bayesian Analysis of Class II M-type SEDs in Cha I
Abstract
The class II stage of a T Tauri star is characterised by the disappearance of the gaseous envelope and the presence of a primordial circumstellar disk . The observed shape of the infrared (IR) region of the spectral energy distribution (SED), where the dust continuum emission peaks, has strong implications for the geometry, structural evolution and physical conditions within the disk. We model the IR SEDs (using 2-24 μm photometry) of 67 class II M-type objects in Cha I using the radiative transfer code of tet{Whitney03a} coupled to a Bayesian parameter estimation. We find that just over half of the objects appear to host `standard' accretion disks, explaining the majority of class II SEDs, in which we observe both the unobscured star and the strong IR signature of its surrounding disk. Roughly a fifth of the objects appear edge-on, resulting in the short wavelength emission being suppressed by outer disk occlusion of the central object and inner disks. At least one object in our sample shows evidence for having a transitional disk with a large inner hole. The remaining objects are categorised as `odd'-looking with highly unusual SEDs. A few of these may be explained by errors in the data, but for the majority it is most likely due to either exotic disk geometry, variability, or binary contamination.
- Publication:
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18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
- Pub Date:
- January 2015
- Bibcode:
- 2015csss...18..137T