A unified theory of cataclysmic variables from self-consistent numerical simulations. (arXiv:2001.05025v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Hillman_Y/0/1/0/all/0/1">Yael Hillman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shara_M/0/1/0/all/0/1">Michael M. Shara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prialnik_D/0/1/0/all/0/1">Dina Prialnik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kovetz_A/0/1/0/all/0/1">Attay Kovetz</a>
The hydrogen-rich envelopes accreted by white dwarf stars from their red
dwarf companions lead to thermonuclear runaways observed as classical nova
eruptions peaking at up to 1 Million solar luminosities. Virtually all nova
progenitors are novalike binaries exhibiting high rates of mass transfer to
their white dwarfs before and after an eruption. It is a puzzle that binaries
indistinguishable from novalikes, but with much lower mass transfer rates, and
resulting dwarf nova outbursts, co-exist at the same orbital periods. Nova
shells surrounding several dwarf novae demonstrate that at least some novae
become dwarf novae between successive nova eruptions, though the mechanisms and
timescales governing mass transfer rate variations are poorly understood. Here
we report simulations of the multiGyr evolution of novae which
self-consistently model every eruption’s thermonuclear runaway, mass and
angular momentum losses, feedback due to irradiation and variable mass
transfer, and orbital size and period changes. The simulations reproduce the
observed wide range of mass transfer rates at a given orbital period, with
large and cyclic changes in white dwarf-red dwarf binaries emerging on kyr to
Myr timescales. They also demonstrate that deep hibernation, (complete stoppage
of mass transfer for long periods), occurs only in short-period binaries; that
initially very different binaries converge to become nearly identical systems;
that while almost all prenovae should be novalike binaries, dwarf novae should
also occasionally be observed to give rise to novae; and that the masses of
white dwarfs decrease only slightly while their red dwarf companions are
consumed.
The hydrogen-rich envelopes accreted by white dwarf stars from their red
dwarf companions lead to thermonuclear runaways observed as classical nova
eruptions peaking at up to 1 Million solar luminosities. Virtually all nova
progenitors are novalike binaries exhibiting high rates of mass transfer to
their white dwarfs before and after an eruption. It is a puzzle that binaries
indistinguishable from novalikes, but with much lower mass transfer rates, and
resulting dwarf nova outbursts, co-exist at the same orbital periods. Nova
shells surrounding several dwarf novae demonstrate that at least some novae
become dwarf novae between successive nova eruptions, though the mechanisms and
timescales governing mass transfer rate variations are poorly understood. Here
we report simulations of the multiGyr evolution of novae which
self-consistently model every eruption’s thermonuclear runaway, mass and
angular momentum losses, feedback due to irradiation and variable mass
transfer, and orbital size and period changes. The simulations reproduce the
observed wide range of mass transfer rates at a given orbital period, with
large and cyclic changes in white dwarf-red dwarf binaries emerging on kyr to
Myr timescales. They also demonstrate that deep hibernation, (complete stoppage
of mass transfer for long periods), occurs only in short-period binaries; that
initially very different binaries converge to become nearly identical systems;
that while almost all prenovae should be novalike binaries, dwarf novae should
also occasionally be observed to give rise to novae; and that the masses of
white dwarfs decrease only slightly while their red dwarf companions are
consumed.
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