(cba:news) more on novae and DQ Hers

Joe Patterson jop at astro.columbia.edu
Sat Aug 2 20:51:06 EDT 2014


Update from the last message.

DQ Her.  Another week of time series from David Cejudo has nailed down 
all the features potentially extractable from the light curve, including 
the spin period to an accuracy of a few microseconds (because the 
long-term ephemeris is specified).  So we're finished with DQ Her.

V1494 Aql.  Wow. The new coverage from Jim Jones and Gordon Myers has 
now established how intricate is the spectrum of periodic signals. 
Apparently there is a "negative" or "nodal" superhump, as well as the 
nodal frequency itself (0.44 c/d), and some other high-frequency stuff 
in the vicinity of 3 w_orb.  Quite a haul... and accompanied by deep 
eclipses, which could enable us to figure where in the binary these 
signals come from.  The signals appear to be well-established, but the 
star is faint and somewhat troubled by a crowding star (include it in 
the aperture); so we GREATLY desire more coverage - the longer the 
better.  Please keep the faith!  About 16.9 magnitude.

V339 Del and HR Del.  The Dolphins are easy to do - both being about mag 
12.5.  But so far, the light curves don't reveal periods; they're not 
long enough, or not of sufficient signal-to-noise.  There's a tentative 
suggestion of a 6,5 hour period in last year's V339 Del data... but it's 
not really evident this year (so far).  Quite a tough star   To do it, 
you need to reduce your internal noise down to 0.02 mag (and preferably 
0.01 mag).  HR Del is not as demanding, but it does require long runs - 
plus, it's quite speculative.

But V1223 Sgr is a great target, and really needs more coverage from all 
longitudes.  It looks like the star is flashing a superhump for the 
first time - but multi-longitude coverage is usually critical in 
establishing this.  Very high priority.
\
And now that August has arrived, it's time for early-season coverage of 
V410 Cas and V455 And (very fast photometry needed) - as well as V2306 
Cyg and RX2133+51 in the midnight sky.

joe
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