yesterday, HST observed successfully HS1055+0939=IU Leo.
Thank you very much for the very detailed monitoring that
you provided - this was extremely helpful to reassure everybody
that the recent outburst was indeed over, and the star was not
up to anything else.
At a first glance, the UV spectrum suggests that the accreting
white dwarf in this long-period dwarf nova may be relatively hot,
which would be consistent with the fact that the system has
relatively frequent dwarf nova outbursts - but we will need a bit
more time for a detailed analysis.