[vsnet-alert 15968] Next HST observations: HS2214+2845 (V513 Peg) & OT J213806.6+261957

Boris Gaensicke Boris.Gaensicke at warwick.ac.uk
Fri Jul 12 23:31:04 JST 2013

Dear All,

thanks a lot for your help in getting this week's
double-feature approved! HST successfully
observed OR And and AX For. OR And behaved
reasonably well, i.e. it did stay in the low state,
where we wanted it to be when HST points at it,
but the data look a bit more complex than anticipated.
In other words, we hoped to get a nice clean spectrum
of the white dwarf, now that the accretion has switched
off for a while, but it is clear that there is still some contribution
to the ultraviolet from other components in the system, and
thus it will take us probably quite a bit of work to distil whatever
photons we got directly from the white dwarf.

In contrast, AX For worked out fantastically. It went into
shortly before the scheduled HST observation,
but there was just enough time for it to fade back to quiescence,
and we got a textbook spectrum of the white dwarf in this
system - this is what the project is all about.

Onto the next two targets:

* HS2214+2845:  Jul 18, 2013 21:08:59 to Jul 19,  01:04:23

* OTJ213806.6+261957 Jul 25, 2013 17:26:50 to  21:05:23

HS2214+2845, aka V513 Peg (I still nostalgically stick to the
HS name) is a U Gem type dwarf nova with relatively infrequent
outbursts - having said that, it just finished the most
That should by all means imply that it can not have another
outburst anytime soon ... but we better prove that hypothesis
with data.

OTJ213806.6+261957 was discovered as a bright WZ Sge
dwarf nova in May 2010, reaching V~8.5, the only other
outburst found on historic plates was in 1942. This CV has
a nearby (~1.5") visual companion, a red / low-mass star,
that is somewhat brighter than the CV in the V-band,
whereas the CV wins at shorter wavelengths (U-band,
and in the ultraviolet where HST will observe).

You will probably struggle to resolve the two stars, thus
please report the combined magnitude for both, which is
V~15 when OTJ213806.6+261957 is in quiescence.

Again, thank you very much for all your help with this project,
the last few targets demonstrated once more how important
the continued monitoring of the HST targets is.

All the best,


For more information on this HST program, see

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