  In the last few years, multiwavelength observations have revealed the
ubiquity of gaps/rings in circumstellar discs. Here we report the first ALMA
observations of HD 92945 at 0.86 mm, that reveal a gap at about 73$\pm$3 au
within a broad disc of planetesimals that extends from 50 to 140 au. We find
that the gap is $20^{+10}_{-8}$ au wide. If cleared by a planet in situ, this
planet must be less massive than 0.6 $M_\mathrm{Jup}$, or even lower if the gap
was cleared by a planet that formed early in the protoplanetary disc and
prevented planetesimal formation at that radius. By comparing opposite sides of
the disc we also find that the disc could be asymmetric. Motivated by the
asymmetry and the fact that planets might be more frequent closer to the star
in exoplanetary systems, we show that the gap and asymmetry could be produced
by two planets interior to the disc through secular resonances. These planets
excite the eccentricity of bodies at specific disc locations, opening radial
gaps in the planetesimal distribution. New observations are necessary to
confirm if the disc is truly asymmetric, thus favouring the secular resonance
model, or if the apparent asymmetry is due to a background galaxy, favouring
the in-situ planet scenario. Finally, we also report the non-detection of CO
and HCN gas confirming that no primordial gas is present. The CO and HCN
non-detections are consistent with the destruction of volatile-rich Solar
System-like comets.
