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The Question
(Submitted December 30, 1998)
What is the smallest nova ever found?
The Answer
I don't know the answer to your question, but there are several types of
things called 'nova'.
Classical novae tend to be, roughly, about the same size, although there is
some variation. Typical absolute magnitudes are around +4.0. Recurrent
novae, which are seen to go off multiple times with intervals of 10 to 50
years, are somewhat dimmer. These two types of novae are thought to be due
to hydrogen buildup on the surfaces of white dwarfs, which accumulate the
material until it suddenly ignites and burns.
Dwarf novae are a different phenomenon, and are typically hundreds of times
fainter. These are due to instabilities in accretion disks. Dwarf nova
can be a variety of sizes, probably down to the point where they can be
classified either as 'nova' or 'brightness fluctuation'.
See
http://imagine.gsfc.nasa.gov/docs/science/know_l2/cataclysmic_variables.html
for more details.
David Palmer and Samar Safi-Harb
for Ask an Astrophysicist
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