(cba:news) a few twists in the program...

Joe Patterson jop at astro.columbia.edu
Thu Jan 26 05:06:30 EST 2006

Dear CBAers,

We've just obtained two additional nights on ASAS0233-10, which firmly
establish the 0.05482(7) d period.  It has a very low amplitude, just 0.02
mag or so; but the light curve is so quiet that this signal is readily
detectable (in the spliced data).  The conventional wisdom on these
stars says that this is Porb, while the superhumps will be vastly bigger
and will arrive a few days later.  I'm awfully eager to see if that
holds up here!  Any trace yet of the of the superhumps?

The sky position on ASAS0233 is pretty bad, but we still have a
fighting chance - for maybe a week or two.  Alas, there's hefty
competition in the evening sky: Eri = SDSS0407-06, which I discussed
before, and a new CV VERY far over in the west at the end of twilight.
That's RX 0023+61, also known as IGR similar-coords.  It's a recently
identified star which is probably an AM Her star - and which therefore
will probably manifest its Porb rather prominently (most AM Hers show a
big photometric signal as their accretion columns wheel around).  For
northern observers, this could be a nice target.  The colors are very,
very red, so an I filter could be helpful - but unfiltered is probably
fine too.  Here's the chart and specs (coords in chart)

(clip, clip)

The USNO mags are B=18.0, R=16.3, I=15.6

Nestor has the chart.  It is star #1 here:



So that's THREE important stars all competing with each other for precious
evening time.  Unfortunately.  I guess I'd have to consider ASAS0233-10 to
have the highest priority; it's in outburst, and it's likely to be a rare
one - not many new dwarf novae are discovered at 12th mag (so it probably
doesn't visit those brightness levels often).

Later in the night, there's T Pyx in the south and UMa 6 in the north
(basically an unstudied 10 hr eclipser).

And then there's RX1050-14 = Hya, touted in the last message.  I take it
all back!  After looking at two nights of coverage, I see that we won't be
able to do this star - it's too faint and the light curve is practically
dead.  Don't even think about it - unless it erupts.  The star I SHOULD
have commended is RX1039-05 (= "Sex" in Downes et al).  This is probably
an AM Her star, but very little is known about it - except that it has a
periodic signal of huge amplitude (about 1.6 mag) and very red colors.
Despite its faintness, I think you'll be handle this star in dark
conditions like we have now.  I'd love to see what light curve you can get
on this!


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