We identify a previously undetected periodicity at a frequency of
49.08±0.01 d−1 (period of 29.34±0.01 minutes) during a
super-outburst of V844 Her observed by TESS. V844 Her is an SU UMa type
cataclysmic variable with an orbital period of 78.69 minutes, near the period
minimum. The frequency of this new signal is constant in contrast to the
superhump oscillations commonly seen in SU UMa outbursts. We searched without
success for oscillations during quiescence using MDM, TESS, and XMM-Newton
data. The lack of a periodic signal in the XMM light curve and the relatively
low X-ray luminosity of V844 Her suggests that it is not a typical IP. We
consider the possibility that the 29 min signal is the result of super-Nyquist
sampling of a Dwarf Nova Oscillation with a period near the 2-minute cadence of
the TESS data. Our analysis of archival AAVSO photometry from a 2006
super-outburst supports the existence of a 29 min oscillation, although a
published study of an earlier superoutburst did not detect the signal. We
compare the X-ray properties of V844 Her with short orbital period intermediate
polars (IP), V1025 Cen and DW Cnc. We conclude that the new signal is a real
photometric oscillation coming from the V844 Her system and that it is unlikely
to be an aliased high-frequency oscillation. The steady frequency of the new
signal suggests that its origin is related to an asynchronously rotating white
dwarf in V844 Her, although the precise mechanism producing the flux variations
remains unclear.Comment: 13 pages, 10 figures, accepted for publication in the Astrophysical
Journa