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supernova · Milky Way, historic naked-eye event

What is Kepler’s Supernova?

The supernova of 1604, the last one in our own galaxy seen with the naked eye.

Worth knowing about Kepler’s Supernova

Its light took about 17,000 years to get here.

Why it stands out
Johannes Kepler followed it for a year and wrote a book about it, De Stella Nova (1606).
What it is
A Type Ia supernova, like Tycho’s: an overfed white dwarf blowing itself completely apart, leaving nothing behind.
How we know: X-ray telescopes measured what the wreckage is made of — heavy in iron, short of oxygen — which is the pattern a detonating white dwarf leaves and a collapsing giant does not.
Kepler’s Supernova — A model, seen from the Earth, with north up.
The numbers
Distance from usabout 17,000 light-years
Discovered1604

We use about 17,000 light-years, from how fast its remnant is growing (Sankrit et al. 2016, 5.1 kiloparsecs); its light curve gives 16,300 (Ruiz-Lapuente 2017). The 20,000 once quoted is out of date.

How anyone knows this

Things like it

Tycho’s SupernovasupernovaBeyond a 150 mm telescopeSN 1987AsupernovaBeyond a 150 mm telescope
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