This coin is not listed in RIC VI for this bust type [DD] and legend. It looks like a star in the right field, but it is not really clear. If not, it is still unlisted. Huvelin listed a coin like this with star in right field (# 53) in her article Les Deux Emissions Londoniennes.
Constantine I
A.D. 310- 312
23mm 4.2gm
CONSTANTINVS P AVG, bust left, radiate helmet, cuirassed, spear over right shoulder and shield on left arm.
COMITI AVGG NN, Sol standing left, chlamys falling from left shoulder, right hand holding up globe, left whip. Star in right field.
In ex. PLN
London
It should be listed after RIC VI London 177
