  A nebular spectrum of the peculiar, low-luminosity type Ia supernova 2010lp
is modelled in order to estimate the composition of the inner ejecta and to
illuminate the nature of this event. Despite having a normally declining light
curve, SN 2010lp was similar spectroscopically to SN 1991bg at early times.
However, it showed a very unusual double-peaked [OI]
$\lambda\lambda\,6300,6363$ emission at late times (Taubenberger et al. 2013).
Modelling of the nebular spectrum suggests that a very small amount of oxygen
($\sim0.05$ M$_{\odot}$), expanding at very low speed ($\sim2000$ km/s) is
sufficient to reproduce the observed emission. The rest of the nebula is not
too dissimilar from SN 1991bg, except that SN 2010lp is slightly more luminous.
The double-peaked [OI] emission suggests that SN 2010lp may be consistent with
the merger or collision of two low-mass white dwarfs. The low end of the SN Ia
luminosity sequence is clearly populated by diverse events, where different
channels may contribute.
