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Abstract: Abridged We present two deep surveys of circumstellar discs aroundsolar-type stars at different ages carried out at 350 micron with the CSO andat 1.2 mm with the IRAM 30-m telescope. The aim of this study is to understandthe evolution timescale of circumstellar debris discs, and the physicalmechanisms responsible for such evolution around solar-type stars. In addition,we perform a detailed characterisation of the detected debris discs.Theoretically, the mass of the disc is expected to decrease with time. In orderto test this hypothesis, we performed the generalised Kendall-s tau correlationand three different two-sample tests. A characterisation of the detected debrisdiscs has been obtained by computing the collision and Poynting-Robertsontimescales and by modelling the spectral energy distribution. The Kendall-s taucorrelation yields a probability of 76% that the mass of debris discs and theirage are correlated. Similarly, the three two-sample tests give a probabilitybetween 70 and 83% that younger and older debris systems belong to differentparent populations in terms of dust mass. We detected submillimetre-millimetreemission from six debris discs, enabling a detailed SED modelling. Our resultson the correlation and evolution of dust mass as a function of age areconditioned by the sensitivity limit of our survey. Deeper millimetreobservations are needed to confirm the evolution of debris material aroundsolar-like stars. In the case of the detected discs, the comparison betweencollision and Poynting-Robertson timescales supports the hypothesis that thesediscs are collision dominated. All detected debris disc systems show the innerpart evacuated from small micron-sized grains.



Author: V. Roccatagliata, Th. Henning, S. Wolf, J. Rodmann, S. Corder, J.M. Carpenter, M. Meyer, D. Dowell

Source: https://arxiv.org/



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