Astronomers using the Gemini North telescope in Hawai‘i have revealed unprecedented detail of Pa 30, the likely remnant of a supernova recorded by Chinese, Japanese, and Arabic observers in the year 1181. New high-definition imaging shows that the nebula’s radial filaments consist of cascading chains of enormous gas knots.
Each individual knot measures roughly four light-days across. The glowing structures reaching outward from the center of Nebula Pa 30 are not continuous streaks as earlier images suggested. Instead, observations captured with the Gemini Multi-Object Spectrograph demonstrate that the debris forms beads on a string, made up of pearl-like gas knots of striking uniformity.
The planetary region of our solar system could fit in each knot about 10 times with room to spare,
Ilaria Caiazzo, a coauthor of the study from the Institute of Science and Technology Austria, said in a press release. The knots are quite strikingly uniform. We are excited to try to model them.
The team observed the nebula using the Gemini Multi-Object Spectrograph. Follow-up imaging on the 2.1-meter Telescope and the Hiltner 2.4-meter Telescope at the NSF Kitt Peak National Observatory also revealed faint nebular emission and radial filaments. Researchers such as Cunningham, Caiazzo, John Raymond, and Scott Kenyon suggest that variations in temperature or density in the surrounding gas played a role in sculpting the debris.
Connecting the 1181 Guest Star to Modern Astronomy
Historical chronicles from Chinese, Japanese, and Arabic astronomers describe a bright guest star appearing in the constellation Cassiopeia between August 4 and August 6, 1181. That temporary beacon remained visible in the night sky for 185 days during the Genpei War in Japan and the reign of Henry II in England. The event stands as one of only five supernovae in the Milky Way documented before the invention of the telescope.
Amateur astronomer Dana Patchick discovered Pa 30 in 2013 while sorting through infrared data from NASA’s Wide-field Infrared Survey Explorer as part of a citizen science project. Follow-up imaging on telescopes at Kitt Peak National Observatory uncovered faint nebular emission and radial filaments, leading researchers to link the object to the historic 1181 explosion based on its estimated age, position, and brightness.
Reliable historical records of stellar explosions extend back only about a thousand years. For all we know, there might well be similar remnants still lurking in the dark in our own galaxy.
Tim Cunningham, University of Warwick
Tracing Type Iax Mechanics Around a Zombie Star
Burning at roughly 200,000 degrees Celsius, the extremely hot surviving star at the center of Pa 30 drives a stellar wind traveling at approximately 16,000 kilometers per second.
Researchers classify the event as a Type Iax supernova, a relatively low-energy thermonuclear explosion that arises from the merger of two white dwarfs. Unlike standard Type Ia explosions that completely destroy the progenitor star, a Type Iax event leaves a surviving core behind. Because the surviving star sits almost exactly at the geometric center of the nebula, scientists infer that the blast imparted no sideways kick or recoil to the remnant, placing a three-sigma upper limit of 14 kilometers per second on the star’s kick across the sky.
Publishing Findings on October 6, 2026
The findings, detailed in a paper titled Detection of knots in the supernova type Iax remnant Pa 30
published in The Astrophysical Journal on October 6, 2026, provide quantitative constraints that competing stellar explosion models must address.
Astronomers hope that the distinct geometry and scale of the newly revealed cosmic pearls will assist in screening massive datasets to uncover similar hidden remnants across the Milky Way.
