New Insights into Classical Novae. (arXiv:2011.08751v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chomiuk_L/0/1/0/all/0/1">Laura Chomiuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metzger_B/0/1/0/all/0/1">Brian D. Metzger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shen_K/0/1/0/all/0/1">Ken J. Shen</a>
We survey our understanding of classical novae: non-terminal, thermonuclear
eruptions on the surfaces of white dwarfs in binary systems. The recent and
unexpected discovery of GeV gamma-rays from Galactic novae has highlighted the
complexity of novae and their value as laboratories for studying shocks and
particle acceleration. We review half a century of nova literature through this
new lens, and conclude:
–The basics of the thermonuclear runaway theory of novae are confirmed by
observations. The white dwarf sustains surface nuclear burning for some time
after runaway, and until recently, it was commonly believed that radiation from
this nuclear burning solely determines the nova’s bolometric luminosity.
–The processes by which novae eject material from the binary system remain
poorly understood. Mass loss from novae is complex (sometimes fluctuating in
rate, velocity, and morphology) and often prolonged in time over weeks, months,
or years.
–The complexity of the mass ejection leads to gamma-ray producing shocks
internal to the nova ejecta. When gamma-rays are detected (around optical
maximum), the shocks are deeply embedded and the surrounding gas is very dense.
–Observations of correlated optical and gamma-ray light curves confirm that
the shocks are radiative and contribute significantly to the bolometric
luminosity of novae. Novae are therefore the closest and most common
“interaction-powered” transients.
We survey our understanding of classical novae: non-terminal, thermonuclear
eruptions on the surfaces of white dwarfs in binary systems. The recent and
unexpected discovery of GeV gamma-rays from Galactic novae has highlighted the
complexity of novae and their value as laboratories for studying shocks and
particle acceleration. We review half a century of nova literature through this
new lens, and conclude:
–The basics of the thermonuclear runaway theory of novae are confirmed by
observations. The white dwarf sustains surface nuclear burning for some time
after runaway, and until recently, it was commonly believed that radiation from
this nuclear burning solely determines the nova’s bolometric luminosity.
–The processes by which novae eject material from the binary system remain
poorly understood. Mass loss from novae is complex (sometimes fluctuating in
rate, velocity, and morphology) and often prolonged in time over weeks, months,
or years.
–The complexity of the mass ejection leads to gamma-ray producing shocks
internal to the nova ejecta. When gamma-rays are detected (around optical
maximum), the shocks are deeply embedded and the surrounding gas is very dense.
–Observations of correlated optical and gamma-ray light curves confirm that
the shocks are radiative and contribute significantly to the bolometric
luminosity of novae. Novae are therefore the closest and most common
“interaction-powered” transients.
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