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(cba:news) dq her pulse maintenance (Joe Patterson) [2011-04-03T13:35:05Z]


DEar CBAers,

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 on this.

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!

joe