October 19, 2026
The 845-Year-Old Supernova That Just Revealed Pearls of Gas
Illustration: The Discovery Wire (generated artwork for this story)
Nearly 850 years ago, a "guest star" blazed in the constellation Cassiopeia. Chinese, Japanese, and Arabic astronomers recorded it independently — visible for 185 days. For centuries its remnant went unidentified, until a citizen scientist spotted the nebula Pa 30 in 2013 and astronomers linked it to that 1181 explosion. Now Gemini North has taken the sharpest picture of it ever, and the remnant turned out to be wearing jewelry.
What astronomers had described as smooth, firework-like streaks are actually chains of gas knots — pearls on a string. Each knot is wide enough to swallow the planetary region of our own solar system about ten times over, with room to spare. And they are strangely, strikingly uniform.
The team — co-led by Ilaria Caiazzo (Institute of Science and Technology Austria) and Tim Cunningham (Center for Astrophysics | Harvard & Smithsonian) — used the Gemini Multi-Object Spectrograph to map the remnant in ionized sulfur (red) and doubly ionized oxygen (blue-green). The sulfur view alone revealed roughly ten times more filamentary features than any previous image. The findings were published in The Astrophysical Journal ("Detection of knots in the supernova type Iax remnant Pa 30").
Pa 30 is the only known object of its kind in the Milky Way. It was left by a Type Iax supernova — a rare, incomplete explosion, probably from a collision between two white dwarfs. Incomplete means exactly what it sounds like: the star survived. A "zombie star" still sits at the remnant's core.
And here's the detail that surprised the researchers: that survivor sits almost exactly at the center of a symmetrical nebula. In most supernovae, an asymmetric blast kicks the surviving star off to one side. "Explosions conserve momentum," Caiazzo explains. "If the explosion itself was perfectly symmetric, the ejecta should also be symmetric, and the surviving star should not receive a substantial kick." Her team measured a precise upper limit on the zombie star's kick speed — and it is surprisingly small. The star barely moves at all. That fact alone may force a rethink of how Type Iax explosions unfold.
Pa 30 lies about 7,500 light-years away, relatively close by cosmic standards — which is exactly why it matters. "We can see this much detail because of Pa 30's proximity to Earth," says Caiazzo. "This proximity makes Pa 30 uniquely valuable for study." Distant Type Iax supernovae appear only as points of light; only in our own galaxy can astronomers resolve the wreckage of such a blast. The plan now is to use Pa 30's fingerprint — those pearl chains, that centered zombie star — to hunt for similar remnants still lurking in the dark.
Three independent cultures recorded the same star in 1181, centuries before the telescope. Eight centuries later, their "guest star" is teaching us how stars can die and walk away.
Source: Phys.org — read the original report
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