Pa 30's supernova image reveals gas knots, not a solved mystery

The red spokes in the Pa 30 image released on 6 October look like a firework frozen in the sky. Look closer and the apparent streaks break into chains of gas knots. That is more than a prettier picture: it gives astronomers another way to test explanations for an unusual stellar explosion. It does not mean they have solved how the explosion happened.

Three things to know

• The October photo release uses Gemini North observations collected in 2025; the explosion is associated with historical records from 1181.
• The researchers resolve chains of gas knots and constrain the surviving star's recoil, rather than identifying a definitive explosion mechanism.
• Read the filter information, dates and uncertainty alongside the spectacular image.

An old explosion, newly resolved

ISTA published its image account on 6 October. Pa 30 is the likely remnant of the supernova recorded by Chinese, Japanese and Arabic astronomers in 1181. Those records describe a new point of light that remained visible for months. The research concerns that historical remnant, not a newly observed explosion. Its journal paper dates the observations to six nights between 26 July and 5 August 2025, using the Gemini Multi-Object Spectrograph on Gemini North in Hawai'i.

The colours carry information

According to ISTA's account of the study, the team examined light emitted by ionised sulphur and doubly ionised oxygen. The released image shows the sulphur emission in red and the oxygen in blue-green tones. The paper describes separate narrowband filters and the processing used to combine and align the observations. These are selected views of the light, not a promise of what your eye would see through a telescope. Read the image as an observational product with a method, not as an unqualified colour snapshot.

More structure, with a resolution limit

The authors report roughly ten times as many resolvable filaments as earlier imaging revealed. Rather than continuous strands, many filaments appear as sequences of compact knots. Their characteristic size is estimated from the sulphur image, where they are only marginally resolved. The oxygen observations show related filamentary structure but do not independently resolve the knots as clearly. That distinction matters: a striking composite should not make every feature look equally well measured.

The apparent regularity is part of the puzzle, not its answer. The paper explains that overlapping filaments along the line of sight complicate a robust measurement of knot spacing. It considers physical explanations involving interactions and instabilities in the gas, and suggests comparing projected models with the data. The observations give those models something harder to explain; they do not select one final origin story.

The surviving star is another clue

Pa 30 contains a surviving central star, sometimes nicknamed a zombie star. Researchers associate the system with a Type Iax supernova, an incomplete thermonuclear explosion rather than the complete destruction familiar from standard Type Ia descriptions. A merger of two white dwarfs is a proposed explanation for Pa 30, not a directly witnessed collision. The analysis fits the nebula's centre from the orientations of its filaments and finds it close to the star's position.

That alignment constrains how strongly the surviving star could have recoiled sideways relative to the nebula. It does not show that the star is motionless in every direction. The paper separates the constraint in the plane of the sky from a three-dimensional estimate that requires an assumption about kick directions. Keeping the measured geometry apart from the model assumptions is essential to understanding what the result establishes.

A discovery assembled across generations

The human chain is unusually long. [ISTA's account](https://ista.ac.at/en/news/like-pearls-in-the-sky/) describes Pa 30's identification in 2013 through a citizen-science archival search, before follow-up observations revealed its structure. The study was co-led by Timothy Cunningham, now at the University of Warwick, and ISTA's Ilaria Caiazzo. Historical records, archival searching and modern instruments contribute different pieces. None substitutes for the others.

Read the caption before sharing

For a science club in Nairobi or a reader in London, the useful habit is the same: check which object is shown, when the observations were made, which light the image selects and what the researchers still cannot distinguish. Those checks prevent a new picture becoming a claim of a new explosion or a settled cause. Pa 30 is compelling precisely because better observations have sharpened the unanswered questions.

Explore the NOIRLab zoomable image alongside its explanation, and find more science coverage on PING's Innovation desk.