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now and then an obscure star briefly

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flares up brightening up to a million

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times

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it's an event called a nova

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the star v906 karani erupted as anova in

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2018. observations from three satellites

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provide new insights into what happened

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nasa's fermi mission has seen 14 novi

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since 2010.

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before then astronomers didn't think

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novae could glow in gamma rays the

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highest energy light

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when a white dwarf pulls material from a

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companion star the gas forms a

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thickening layer that eventually erupts

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in a thermonuclear fireball

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a nova is born

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led by a team from michigan state

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university astronomers studied v906

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karani using high energy data from fermi

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nasa's nustar x-ray telescope

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and invisible light from a canadian

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satellite named bright toronto

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shaped by the orbital motion of the

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stars the explosion debris first forms a

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thick expanding ring around the system

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then

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after 10 days or so

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fast outflows likely driven by residual

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fusion on the white dwarf strike the

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ring the resulting shock waves produce

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gamma-ray and optical flares that

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radiate away most of the novus energy

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these observations provide the first

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direct evidence that shockwaves can

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power most of

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explosion's visible light

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figuring out how they work in nearby

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novi will help us understand more