(cba:news) more on novae and DQ Hers
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.
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