ah, the smell of fresh periods fills the air

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Thu, 24 Sep 1998 16:47:38 -0400 (EDT) · jop_at_astro.columbia.edu

Dear CBAers,                                          Sept. 24, 1998.

Well, after an intense week on CP Eri by Jonathan at MDM (Kitt Peak),
that li'l ol' star has coughed up its periods!  Not all of 'em, but we
managed to find periodic signals at 1700(1) and 1717(2) s, and the
slight instability in the latter suggests identification of these as,
respectively, orbit and superhump.  It's another case (there are many
now) which violates the old rule that "superhumps are not seen in
quiescence".

Oh, what a star!  Very large signals, and surprisingly easy despite the
daunting magnitude (about 19.7).  I always thought that somewhere among
the helium CVs (the "AM CVn stars"), there would be an easy one -- like
VW Hyi among ordinary dwarf novae.  Seems only fair.  CP Eri was our
last chance.  Kudos to Tim Abbott, the pioneer on this wonderful star.

There's still lots we don't know.  It "erupts" to 16.5 fairly often,
but we dunno how often.  Since the observing season is just beginning,
it would be nice if people could get snapshot magnitudes that might
define this critical number.  Of course time series would be even
better.  Who can help?

Now back to the "ordinary" (hydrogen-rich) dwarf novae.  There are
three erupters in tonight's sky we're trying to cover: V419 Lyr, V630
Cyg, and V1028 Cyg.  V419 Lyr is about 15.5, and we're still not
absolutely sure it's a superoutburst (but I think so).  The two Cygnus
stars are about 15 and humping along nicely - probably they'll continue
for another 4-7 days, and we'd love to track those waves as long as we
can.  Pick one of 'em and track it down to oblivion with long time
series.

And the long-term programs continue on HL Aqr, TT Ari, and V592 Cas
(all needing fairly long time series); and FO Aqr and AO Psc (short
observations OK, though longer is always better).

There's a report that KK Tel is in outburst (15).  If it's a super,
then this is the moment for australites to pounce.  We worked hard to
find an accurate quiescent (orbital) period last year - now it would
be great to pair that with a shiny new superhump period!

      joe