A stellar census of the nearby, young 32 Orionis group
  The 32 Orionis group was discovered almost a decade ago and despite the fact
that it represents the first northern, young (age ~ 25 Myr) stellar aggregate
within 100 pc of the Sun ($d \simeq 93$ pc), a comprehensive survey for members
and detailed characterisation of the group has yet to be performed. We present
the first large-scale spectroscopic survey for new (predominantly M-type)
members of the group after combining kinematic and photometric data to select
candidates with Galactic space motion and positions in colour-magnitude space
consistent with membership. We identify 30 new members, increasing the number
of known 32 Ori group members by a factor of three and bringing the total
number of identified members to 46, spanning spectral types B5 to L1. We also
identify the lithium depletion boundary (LDB) of the group, i.e. the luminosity
at which lithium remains unburnt in a coeval population. We estimate the age of
the 32 Ori group independently using both isochronal fitting and LDB analyses
and find it is essentially coeval with the {\beta} Pictoris moving group, with
an age of $24\pm4$ Myr. Finally, we have also searched for circumstellar disc
hosts utilising the AllWISE catalogue. Although we find no evidence for warm,
dusty discs, we identify several stars with excess emission in the WISE W4-band
at 22 {\mu}m. Based on the limited number of W4 detections we estimate a debris
disc fraction of $32^{+12}_{-8}$ per cent for the 32 Ori group.
