White_dwarf2 - Each nova adds mass to the WD ( not all...

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White dwarfs (WD) Accreted material (mostly H) builds up in a thin layer on the White Dwarf Surface The temperature of accreted matter eventually becomes hot enough for hydrogen fusion (~10 million K) Fusion begins suddenly and explosively, causing a nova. Nova (Novae) …is a WD that brightens suddenly due to rapid H burning on its surface (that is not a supernova!) Typically brightens to ~100,000 Lsun Fade after a few weeks (ejected material, may shine longer) Mass transfer resumes If enough mass transfers, anther nova will occur.
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Unformatted text preview: Each nova adds mass to the WD ( not all ejected) What happens if mass grows to 1.4 Msun? WD Supernova? o At WD limit, temperature exceeds that needed to fuse Carbon. Entire star fuses. o Explodes as a “carbon bomb” Two types of supernova 1) massive star supernova: • iron core of massive stars reaches the WD limit and collapses into a neutron star, causing explosion. 2) WD supernova: • Carbon fusion suddenly begins as a WD in close binary system reaches WD limit, causing total explsion....
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This note was uploaded on 04/08/2011 for the course ASTRO 1020 taught by Professor White during the Winter '09 term at UGA.

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