TITLE: PHOTOMETRIC STUDY OF CLASSICAL NOVA V1674 Her

AUTHORS: S.Yu. Shugarov, M.D. Afonina

ABSTRACT:
An analysis of the new UBVRcIc observations of V1674 Her (outburst was July, 12, 2021) obtained by the 
authors shows that the star is a very fast Nova, with parameters T2 = 1.1d, T3 = 2.2d. The orbital period at 
the brightness decline, at 39 - 56 days after the outburst, we found as 0.15290 d, the shape of the light 
curve featured two unequal minima separated by half a period, the amplitude of the observed wave being 0.12 mag.

Variations of color indices was found and depending on the time after the outburst and also
on the phase of the orbital period.

The object is unique in that has the steepest brightness-decline gradient among all known Classical Novae.
Likely, it is an intermediate polar with a white-dwarf rotation period of 8m 21s and orbital period close 
to 3h 40m. Also, it is a member of the neon Novae class, has a large outburst amplitude, reaching 14 mag; 
it is a gamma-ray source and an SSS source.