[vsnet-alert 15521] Re: Next HST observations: PU CMa & IY UMa

[Boris Gaensicke]

Dear All,

well, that was an exciting week: V485 Cen went
into outburst March 12th, with the HST observations
scheduled for March 16th ... you can imagine that
STScI were rather nervous, and it was a quite
close call to get permission to go ahead with
the HST observations. We got the ultraviolet
spectrum, and as expected, it looks different from
the other stars we observed so far, as the companion
of V485 Cen is not a normal low-mass main-sequence
star, but the left-over nuclear evolved core of a
previously more massive star that got stripped of its
envelope - the first one of this small class of stars
where we managed to get a good spectrum.

Your very intense monitoring of the star during
and following the outburst was the key to obtain
permission to go ahead with the HST observations,
as it demonstrated that this was not a superoutburst,
and that V485 Cen was back in quiescence in time
for the HST observations.

But, no time to rest: the next two targets on the
HST schedule are:

PU CMa: Mar 22, 2013 00:00:43 to Mar 22, 2013 02:36:08

and

IY UMa: Mar 29, 2013 23:43:52 to Mar 30, 2013 02:18:13

Both are short-period SU UMa type dwarf novae, with
superoutbursts occurring very roughly once a year, and
normal outbursts every few months. IY UMa is
eclipsing.

Both will be dangerously bright during outburst,  thus,
please keep a very close eye on them up until the scheduled
time of the HST observations - this week just showed
how important your monitoring is for this project!

Best wishes,

Boris

-----------------------------------------------------------------------------------------------------
For more information on this HST program, see

http://deneb.astro.warwick.ac.uk/phsdaj/public_html/12870/
http://deneb.astro.warwick.ac.uk/phsdaj/public_html/12870/Targets.html