The Big Sibling of AU Mic: A Cold Dust-rich Debris Disk around CP−72 2713 in the β Pic Moving Group

Abstract

Analyzing Spitzer and Herschel archival measurements we identified a debris disk around the young K7/M0 star CP−72 2713. The system belongs to the 24 Myr old β  Pic moving group. Our new 1.33 mm continuum observation, obtained with the Atacama Large Millimeter/submillimeter Array 7 m array, revealed an extended dust disk with a peak radius of 140 au, probably tracing the location of the planetesimal belt in the system. The disk is outstandingly large compared to known spatially resolved debris disks and protoplanetary disks around stars of comparable masses. The dynamical excitation of the belt at this radius is found to be reconcilable with planetary stirring, while self-stirring by large planetesimals embedded in the belt can work only if these bodies form very rapidly, e.g., via pebble concentration. By analyzing the spectral energy distribution, we derived a characteristic dust temperature of 43 K and a fractional luminosity of 1.1 × 10 −3 . The latter value is prominently high; we know of only four other similarly dust-rich Kuiper Belt analogs within 40 pc of the Sun.