(cba:news) targets for January 2015: T Pyx, CP Pup, HZ Pup, and especially ASASSN-14mv

Joe Patterson jop at astro.columbia.edu
Wed Dec 31 14:33:26 EST 2014

Dear CBAers,

Out with the old (except DQ Hers), in with the new (or newly re-acquainted).

ASASSN-14ei has had a glorious year, with steady observation from NZ 
(Bob Rea), South Africa (Berto), Chile (Josch), and especially Australia 
(Gordon).  5 solid months, nearly every night, spanning the Earth, with 
the star showing a superoutburst followed by 12 echoes (and counting). 
The superhumps endure throughout, and their coherence (stability in 
phase) is amazing.  Basic period of 42.9 minutes, with numerous 
harmonics.  Wow.  Apparently the helium stars can manage much better 
stability than the H guys.  Food for thought (but I doubt I can figger 
it out).

Anyway, it's time to END THE CAMPAIGN.  Evening twilight is shortening 
the runs, and there's just too much low-hanging fruit out there to keep 
going.  UNLESS there's another 12th magnitude superoutburst - *that* 
would be worth an encore performance.

There are *numerous* excellent targets well-placed in the southern sky 
this month.  These are:

1. T Pyx. Occasional all-night (or very lengthy) runs will do the job. 
We need only ten more over the whole Jan-Feb-Mar observing season.

2. HZ Pup (=Nova Pup 1963).  Last year we found the periodic signals 
confirming its identity as a DQ Her star.  Now it's time to test the 
long-term stability (certify its remembrance of phase from 2014 to 
2015).  We definitely want long runs - and the most desirable time 
window is the next two weeks (subject to moonlight limitations of 
course), because we have an observing run on the MDM 2.4m then.  We 
can't get long runs on Puppis of course, but can provide observations 
linking South Africa to AU/NZ.  About 17th mag.

3. CP Puppis.  Prime season for this fascinating star.  We seem to know 
its Porb (88 minutes), and we know the large photometric humps occur at 
a slightly longer period.  Sounds familiar, right?  Au contraire!  The 
variations are not understandable as superhumps, and are much less 
stable.  To understand them, we need to get coverage as global as 
possible.  Perhaps this should wait until the present bright-moon period 
is over.

4. V959 Mon.  Definitely want lengthy runs for this 2012 nova.

The two very high priority stars are:

1. WX Ari.  The lengthy 2014 low state continues, with the star at 19th 
magnitude. I know it sounds quixotic, but if you can possibly get a 3-4 
hour time series on this star - maybe with a red filter to subdue 
moonlight - it would be very rewarding!

2. ASASSN-14mv.  A star (dwarf nova??) just erupted, and just 
discovered.  See
Josch's first night on this star, just communicated on cba-chat, show 
obvious fast waves in this star (I assume it's a star).  very well 
placed for lenthy runs.  Around 13-14 magnitude.  A sensational way to 
end one year and start the next!

The other good northern targets are DQ Hers (intermediate polars).  You 
know the drill on these guys, and maybe you even have your favorites. 
Most of them need coverage, and most can accept several-hour runs. 
Longer is always better, but a few hours is usually good enough.  The 
ones particularly starved for coverage are: HT Cam, V647 Aur, V667 Pup, 
DW Cnc, and WX Pyx.

Happy observing in 2015!

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