A cloudy model for the Circumnuclear Disk in the Galactic Centre

We present a first attempt to construct an analytic model for a clumped gas and dust disk and apply it to the Galactic Centre. The clumps are describe d as isothermal spheres partially ionized by the external UV radiation fiel d. The disk structure formed by the clouds is described as a quasi standard continuous accretion disk using adequately averaged parameters of the disc rete cloud model. The viscosity in the Circumnuclear Disk is due to partial ly inelastic cloud-cloud collisions. We find two different solutions for th e set of equations corresponding to two stable cloud regimes: (i) the obser ved molecular clouds and (ii) much lighter and smaller clouds which corresp ond to the stripped cores of the observed clouds. It is shown that the resu lting physical characteristics of the heavy clouds and the disk are in very good agreement with all comparable observations at multiple wavelengths. A mass accretion rate of M similar or equal to 10(-4) M-circle dot yr(-1) fo r the isolated Circumnuclear Disk is inferred. We propose that the Circumnu clear Disk has: a much longer lifetime (similar to 10(7) yr) than previousl y assumed.