Research Unit “Debris Disks in Planetary Systems”

Which debris disks may harbor planets?

To be observable as a debris disk, a planetesimal belt must be stirred, i.e., the relative velocities of planetesimals must be sufficienly high for for a collisional dust production. Stirring may come either from large planetesimals themselves ('self-stirring') or from planets orbiting in the disk cavity. We have computed the timescales of self-stirring (filled areas in the figure) and compared them to a sample of prominent debris disks with known ages and radial extents (horizontal bars). Disks with outer regions lying below the filled areas are incompatible with being self-stirred and thus require planets as stirrers. In our sample, these are 49 Cet, HD 95086, and HR 8799, of which the latter two are already known to have planets.



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