  We present the discovery of long-period, low-amplitude, g-mode pulsations in
the intermediate He-rich hot subdwarf (sdOB) star Feige 46. Up until now only
one other He-enriched sdOB star (LS IV -14116) was known to exhibit such
pulsations. From our ground-based light curves of Feige 46, we extracted five
independent periodicities ranging from 2294 s to 3400 s. We fitted our
low-resolution, high signal-to-noise optical spectrum of the star with our grid
of non-LTE model atmospheres and derived the following atmospheric parameters:
Teff = 36120 $\pm$ 230 K, log g = 5.93 $\pm$ 0.04 and log N(He)/N(H) = -0.32
$\pm$ 0.03 (formal fitting errors only). These parameters are very similar to
those of LS IV -14116 and place Feige 46 well outside of the instability strip
where the hydrogen-rich g-mode sdB pulsators are found. We used the Gaia
parallax and proper motion of Feige 46 to perform a kinematic analysis of this
star and found that it likely belongs to the Galactic halo population. This is
most certainly an intriguing and interesting result given that LS IV -14116 is
also a halo object. The mechanism responsible for the pulsations in these two
peculiar objects remains unclear but a possible scenario involves the
$\epsilon$-mechanism. Although they are the only two members in their class of
variable stars, these pulsators appear to have more in common than just their
pulsation properties.
