(cba:news) dq her pulse maintenance
jop at astro.columbia.edu
Sun Apr 3 09:35:02 EDT 2011
The ER UMa campaign is going very, very well: 70 nights of nearly
continuous data! But as it gets better and better, the *percentage*
improvement of coverage gets less and less. The main goal -
understanding how the negative superhump interacts with the various
normal and super-outbursts - is likely to be significantly enhanced by
more coverage. So *some* coverage of the star, especially near
quiescence at V=15, is still quite desirable. But I'm inclined to pull
the plug on it now as a major campaign target.
Likewise for SDSS1339+48. The super-outburst is long over, and, as is
typical of these WZ Sge stars, the superhump lingers for a long time -
like a headache after you bump your head. I'd say the law of
diminishing returns has knocked this star off our menu. The star at
quiescence has white-dwarf (rapid) pulsations, so at some point we want
to revisit to see if they have returned. But that's mainly a project
for 2012, not now. Sayonara.
Finally, YZ Cnc. Another long and successful campaign, with coverage in
quiescence, normal outburst, and superoutburst... and 2 months long.
I'd be inclined to end this campaign also. However, Arek Olech will be
writing this one up, so I'll give him the chance to register an opinion
Unless another glamor star fires up, we've got an opportunity to do some
serious maintenance work on the ephemerides of DQ Her pulses.
Time-series photometry early and late in the observing season is always
of extra value since it constrains the cycle count in the typically
8-month gap between seasons. And (northern) spring is ideal since it
can service the two main clusters of DQ Hers: in the winter and summer
skies. Sorry for the long list, but here are evening stars who can
really use the attention:
HT Cam, RX0636+35, RX0704+26, Swift0732-13, WX Pyx, DW Cnc (long run
only), PQ Gem, MU Cam. Vaguely in order of declining priority, but
really, it's not possible to predict which stars will have high
potential for high-impact observations, since it depends on the rate of
period change - which is unknown, and is the point of observing them!
Unlike our usual observing philosophy, these stars don't need
particularly long runs (3 hrs is plenty), and you can do a menagerie of
stars without concern about diluting your efforts.
And here are morning stars, with same comments applying: DQ Her (maximum
20 s cycle time), NY Lup, RX1654-19, V4743 Sgr, RX1730-05, and V1223 Sgr.
And two middle-of-night guys: EX Hya and YY Dra. The latter would
probably repay observation in *blue* light - and probably would need
quite long nightly observations (there's an M dwarf which is annoyingly
strong in the spectrum, and needs to be subdued.
Finally, there's AM CVn and HP Lib. Very, very good targets, in the
prime of their seasons... and if you like the all-night targets, these
are the stars for you!
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