(cba:news) Old and new targets

Joe Patterson jop at astro.columbia.edu
Fri Jul 1 06:35:38 EDT 2005

Dear CBAers,

The star of the month, Var Nor 05 = ASAS1600-48, seems like it's about to
dive off our radar screens.  I've analyzed the data coming in and found
that it really does deliver on its advance notices - the outburst really
did seem like a WZ Sge-type, with a superhump sideband structure strongly
insinuating an orbital period 1.0% less then P(superhump).  This was a
great thrill.  These stars of very small Psh-Porb are likely to be the
oldest of CVs, and the size of that period excess is usually the best
indicator of its age (because it signifies the mass of the secondary).

It would be nice to continue that campaign further... and it might be
possible, since the star is now engaging in echo outbursts.  If you can
keep tracking and are willing to struggle with the field and the
faintness, please do!  But from this latitude I really don't have much
idea what the star is doing... so you need to leaven (or replace) my
advice with common sense!

Here are the other southern targets du jour:

1. V1494 Aql.  OK, it's +5 deg dec, but still.... We will conclude our
4-year study of this classical nova (1999) this year.  No observations
this year, but when last seen it was bright enough for CBA work.  Nice
3-hour period, origin not yet securely known.

2. Other well-placed southern old novae.  Berto tracks the recent ones
pretty faithfully... and there are a whole bunch.  Berto, which do you
think is a good candidate for us?

3. RX1730-05 (Oph).  Actually this is first priority (for sure), but
Jennie tells me it has gone faint.  If you can do it, this is the guy!
There's a quite fast period it would be nice to track; but even if your
exposure times knock it out, there's also the orbital period to find.
A candidate at 16 hours - difficult for most observers, but red meat for
the CBA - especially with Paul Warhurst still in Argentina.

4. V442 Oph.  Pretty inviting target for CBA weaponry.  We've not managed
a really good campaign since 1995, and it would be lovely to have one.
Very well placed in the sky!

And in the NORTH:

1. RX1730-05 (Oph), subject to the above brightness worries.

2. V1494 Aql, a star for all latitudes.

3. IX Dra and MN Dra.  These are two dwarf novae with very small superhump
period excesses (Psh-Porb) reported.  The data seemed kinda uncertain in
both cases, but this is an important question to be really sure of!  In
fact, both of these are overall mystery stars with nearly everything up in
the air - the recurrence time, the eruption shapes, the values of Psh and
Porb, the amount of time spent at max and min, etc.  I especially
recommend IX Dra for now, though the observing seasons are long.  These
are stars for which even *snapshot* magntiudes are useful - though of
course our main nutrient is long time series.

I'm heading off to a conference in the Netherlands tomorrow night. Pretty
sure I'll have email there, though.


Oh, by the way, we have a big PASP paper which I believe will be accepted
in the next 2 weeks: with coauthors Harvey, Fried, Rea, Monard, Cook,
Skillman, Vanmunster, Bolt, McCormick, Krajci, Jensen, Gunn, Butterworth,
Foote, Bos, Masi, and Warhurst.  All-star cast!  Contains results for
*many* of our stars... with many more still in the hopper.  We'll send a
pdf file to authors, or a paper copy (send mailing address) if you request

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