(cba:news) AA Dor and T Pyx
jop at astro.columbia.edu
Sun Dec 10 07:04:16 EST 2017
I'm getting close to finishing the IM Nor paper. Only a few CBAers
contributed to this one (Gordon, Berto, and Paul Warhurst so far); it's
very faint, far southern, and obscure - discouragements to most of us.
This paper will go into some detail concerning the irradiation of the
donor star by the hot white dwarf, in the aftermath of a nova explosion.
I would like to include light curves from a classic supersoft binary and
a classic hot-subdwarf binary - stars in which heating effects are truly
obvious and well-known. It's hard to convince people of the importance
of heating in CVs; some think it's obvious, and others think it's
impossible. And I think there's a third group ("maybe true but of no
AA Dor is a very famous star with a beautiful light curve - primary
eclipse, secondary eclipse, and sinusoidal wave obviously signifying the
heating of the brown-dwarf secondary by the hot-subdwarf primary. It
has been analyzed in great detail - it competes with HW Vir as the
prototype of the class (sort of like SS Cyg and U Gem battling for the
honors among dwarf novae).
CBA light curves of AA Dor would be a nice addition to our paper. We
already have a beautiful orbital light curve of a supersoft (QR And),
and AA Dor would bookend it nicely. It would be a nice primer on
heating effects - in a detached binary (AA Dor) and a full
accretion-disk system (QR And). At magnitude 11.5, AA Dor is blindingly
bright; I recommend a V filter if you have one you like - although
unfiltered is OK too if you scrupulously avoid large airmass. As befits
a simple star, 6 hours is both the binary period and the right
ascension. Nice holiday gift.
Ali is the greatest,
But now hear the latest:
Is what we wish for.
The holidays have also brought T Pyx back in the sky. Let's get going
on this star. Southern USA observers can contribute, as well as -
obviously - the australites. Each new season brings peril to our
favorite theory: death by heating.
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