  LoTr 5 is a planetary nebula with an unusual long-period binary central star.
As far as we know, the pair consists of a rapidly rotating G-type star and a
hot star, which is responsible for the ionization of the nebula. The rotation
period of the G-type star is 5.95 days and the orbital period of the binary is
now known to be $\sim$2700 days, one of the longest in central star of
planetary nebulae. The spectrum of the G central star shows a complex H$\alpha$
double-peaked profile which varies with very short time scales, also reported
in other central stars of planetary nebulae and whose origin is still unknown.
We present new radial velocity observations of the central star which allow us
to confirm the orbital period for the long-period binary and discuss the
possibility of a third component in the system at $\sim$129 days to the G star.
This is complemented with the analysis of archival light curves from SuperWASP,
ASAS and OMC. From the spectral fitting of the G-type star, we obtain a
effective temperature of $T_{\rm eff}$ = 5410$\pm$250 K and surface gravity of
$\log g$ = 2.7$\pm$0.5, consistent with both giant and subgiant stars. We also
present a detailed analysis of the H$\alpha$ double-peaked profile and conclude
that it does not present correlation with the rotation period and that the
presence of an accretion disk via Roche lobe overflow is unlikely.

Solar and Stellar Astrophysics