The big sibling of AU Mic: a cold dust-rich debris disk around CP-72
  2713 in the $\beta$ Pic moving group
  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 24Myr
old $\beta$ Pic moving group. Our new 1.33mm continuum observation, obtained
with the ALMA 7-m array, revealed an extended dust disk with a peak radius of
140au, probably tracing the location of the planetesimal belt in the system.
The disk is outstandingly large compared to known spatially resolved debris
disks and also to 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 43K and a fractional luminosity of
1.1$\times$10$^{-3}$. The latter value is prominently high, we know only four
other similarly dust-rich Kuiper-belt analogs within 40pc of the Sun.
