(cba:news) Nova Del 2013, a last hurrah
jop at astro.columbia.edu
Wed Dec 4 10:46:25 EST 2013
Several recent ATels discuss the strong supersoft source now visible in
Nova Del 2013 = V339 Del and also the ~56 second periodicity in X-rays.
The origin of the supersoft emission has got to be the hot white
dwarf... and if we can see it basically unobscured, then there's a
decent chance (far from certain, but a decent chance) that the secondary
star can also. And if it does, then we ought to see a periodic
modulation as the heated face of the secondary wheels around in binary
That's a good reason to REINSTATE V339 Del as a primary target, despite
the awkwardness of Delphinus in December. If we can stitch together
enough longitudes, we can perhaps still cover enough of the day to see a
The 56 s period is a different matter. Its origin is far from clear,
but because the timescale is so short, it's likely to be *something*
associated with the white dwarf - which we can now see. So that's
another thing to look for, and that search is not particularly hampered
(slightly, but not that much) by the poor sky position. You do need a
total cycle time less than ~20 s to detect this, though. And if you can
possibly get that cycle time down ~12 s, you can also cover the
possibility that most of the power is in the second harmonic (at 28 s.
Sometimes that happens... but then again, if you're mainly just reading
out rather than collecting photons, then it's not a good trade-off.
Give it a try. Each day is another 4 minutes lost!
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