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arXiv · 1106.4276

An evla and carma study of dusty disks and torii with large grains in dying stars

R. Sahai·M. J. Claussen·S. Schnee·M. R. Morris·C. Sánchez Contreras
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Abstract

We report the results of a pilot multiwavelength survey in the radio continuum (X, Ka and Q bands, i.e., from 3.6 cm to 7 mm) carried out with the EVLA in order to confirm the presence of very large dust grains in dusty disks and torii around the central stars in a small sample of post-AGB objects, as inferred from millimeter and sub-millimeter observations. Supporting mm-wave observations were also obtained with CARMA towards three of our sources. Our EVLA survey has resulted in a robust detection of our most prominent submm emission source, the pre-planetary nebula IRAS 22036+5306, in all three bands, and the disk-prominent post-AGB object, RV Tau, in one band. The observed fluxes are consistent with optically-thin free-free emission, and since they are insignificant compared to their submm/mm fluxes, we conclude that the latter must come from substantial masses of cool, large (mm-sized) grains. We find that the power-law emissivity in the cm-to-submm range for the large grains in IRAS22036 is nu^{beta}, with beta=1-1.3. Furthermore, the value of beta in the 3 to 0.85 mm range for the three disk-prominent post-AGB sources (beta < or = 0.4) is significantly lower than that of IRAS22036, suggesting that the grains in post-AGB objects with circumbinary disks are likely larger than those in the dusty waists of pre-planetary nebulae.

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R. Sahai, M. J. Claussen, S. Schnee, M. R. Morris, C. Sánchez Contreras. 2011-06-21. An evla and carma study of dusty disks and torii with large grains in dying stars. https://doi.org/10.1088/2041-8205%2F739%2F1%2Fl3

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