Astronomers have unveiled the intricate structure of Pa 30, a rare supernova remnant in our galaxy, using advanced telescopes. The object, linked to a 12th-century “guest star” observed across Asia and the Middle East, offers new insights into Type Iax supernovae, where the star survives partially.
The supernova remnant Pa 30, captured in striking detail by the Gemini North Telescope in Hawai‘i, has revealed a complex structure that challenges existing models of stellar explosions. This object, the only known example of its kind in the Milky Way, is the aftermath of a star that exploded in 1181, as recorded by Chinese, Japanese, and Arabic astronomers. The event left behind a “zombie star”—a surviving core—surrounded by delicate filaments of gas and dust, some 4 light-days in diameter.
A Cosmic Puzzle Spanning 845 Years
Historical records from 1181 describe a “guest star” visible for 185 days, now believed to be the explosion that created Pa 30. Modern observations, including those from the Gemini North Telescope, have revealed the remnant’s unusual morphology. Unlike typical supernova remnants, Pa 30’s structure resembles a string of pearls, with elongated knots stretching across space. This configuration, described as “intricate” by researchers, suggests a unique formation process.
We can see this much detail because of Pa 30's proximity to Earth,
said Ilaria Caiazzo, from the Institute of Science and Technology Austria, who helped lead the work. This proximity makes Pa 30 uniquely valuable for study.
The object lies about 7,500 light-years from Earth, a relatively short distance in cosmic terms, allowing astronomers to examine its core in unprecedented detail.
Type Iax Supernovae: A Mysterious Class
Pa 30 is classified as a Type Iax supernova, a rare category where the explosion does not fully destroy the star. Scientists believe these events occur when two white dwarfs—the dense, Earth-sized objects that stars collapse into as they die—collide. Unlike typical supernovae, which obliterate their progenitors, Type Iax explosions leave behind a “zombie star” at the center. This surviving core, observed in Pa 30, is unusually hot and emits strong stellar winds, shaping the surrounding filaments.
The study, published in The Astrophysical Journal, highlights the rarity of such events. Though Pa 30 is the only known example of its kind, it might not be alone in our galaxy,
said Tim Cunningham, from the University of Warwick, who also co-led the work. There may be others out there waiting to be found.
Unveiling the Past, Guiding the Future
As telescopes become more sensitive, astronomers hope to identify more objects like Pa 30. For now, Pa 30 remains a rare window into a cosmic phenomenon that defies easy explanation, bridging ancient observations with cutting-edge astrophysics.
“The explosion sits about 7,500 light years away from Earth. It is the only known object of its kind in the Milky Way – and, though other examples have been seen in other galaxies, its relative proximity means that we can see the leftovers from the explosion at its core.”
Ilaria Caiazzo, Institute of Science and Technology Austria