  AQ Col (EC 05217-3914) is one of the first detected pulsating subdwarf B
(sdB) stars and has been considered to be a single star. Photometric monitoring
of AQ Col reveals a pulsation timing variation with a period of 486 days,
interpreted as time-delay due to reflex motion in a wide-binary formed with an
unseen companion with expected mass larger than 1.05 $M_\odot$. The optical
spectra and color-Magnitude diagram of the system suggested that the companion
is not a main sequence star but a white dwarf or neutron star. The pulsation
timing variation also shows that the system has an eccentricity of 0.424, which
is much larger than any known sdB long period binary system. That might be due
to the existence of another short period companion to the sdB star. Two optical
spectra obtained on 1996 December $5^{\rm th}$ show a radial velocity change of
49.1~km/s in 46.1 minutes, which suggests the hot subdwarf in the wide-binary
is itself a close-binary formed with another unseen white dwarf or neutron star
companion; if further observations show this interpretation to be correct, AQ
Col is an interesting triple system worthy of further study.
