  SN 2010lp is a subluminous Type Ia supernova (SN Ia) with slowly-evolving
lightcurves. Moreover, it is the only subluminous SN Ia observed so far that
shows narrow emission lines of OI in late-time spectra, indicating unburned
oxygen close to the centre of the ejecta. Most explosion models for SNe Ia
cannot explain the narrow OI emission. Here, we present hydrodynamic explosion
and radiative transfer calculations showing that the violent merger of two
carbon-oxygen white dwarfs of 0.9 and 0.76 solar masses, respectively,
adequately reproduces the early-time observables of SN 2010lp. Moreover, our
model predicts oxygen close to the centre of the explosion ejecta, a
pre-requisite for narrow OI emission in nebular spectra as observed in SN
2010lp.
