  Fourteen years after its eruption as a classical nova (CN), V1047 Cen (Nova
Cen 2005) began an unusual re-brightening in 2019 April. The amplitude of the
brightening suggests that this is a dwarf nova (DN) eruption in a CN system.
Very few CNe have had DN eruptions within decades of the main CN outburst. The
14 years separating the CN and DN eruptions of V1047 Cen is the shortest of all
instances recorded thus far. Explaining this rapid succession of CN and DN
outbursts in V1047 Cen may be challenging within the framework of standard
theories for DN outbursts. Following a CN eruption, the mass accretion rate is
believed to remain high $(\dot{M}\sim10^{-8}$M$_\odot$yr$^{-1})$ for a few
centuries, due to the irradiation of the secondary star by the still-hot
surface of the white dwarf. Thus a DN eruption is not expected to occur during
this high mass accretion phase as DN outbursts, which result from thermal
instabilities in the accretion disk, and arise during a regime of low mass
accretion rate $(\dot{M}\sim10^{-10}$M$_\odot$yr$^{-1})$. Here we present
near-infrared spectroscopy to show that the present outburst is most likely a
DN eruption, and discuss the possible reasons for its early occurrence. Even if
the present re-brightening is later shown to be due to a cause other than a DN
outburst, the present study provides invaluable documentation of this unusual
event.
