New observations from the Gemini North telescope on Maunakea in Hawai‘i reveal the most detailed view yet of Pa 30, a supernova remnant about 7,500 light-years away. Its distinctive streaks of gas look like sparks shooting outward. But zoom in, and those seemingly smooth trails turn out to be chains of knots, resembling pearls on a string. And these are some very big pearls.
“The planetary region of our solar system could fit in each knot about 10 times with room to spare,” astrophysicist Ilaria Caiazzo, an assistant professor at the Institute of Science and Technology Austria, said in a statement. “The knots are quite strikingly uniform. We are excited to try to model them.”
The findings, from a team co-led by Caiazzo and astrophysicist Tim Cunningham, are published in The Astrophysical Journal.
An explosion with a medieval paper trail
Researchers consider Pa 30 the likely remains of SN 1181, a supernova recorded by observers in Chinese, Japanese, and Arabic historical sources in 1181. It remained visible in the constellation Cassiopeia for 185 days.
But connecting those accounts to something astronomers could study today took centuries. Amateur astronomer Dana Patchick discovered Pa 30 in 2013 while examining data from NASA’s Wide-field Infrared Survey Explorer as part of a citizen science effort. The object turned out to have an especially unusual resident: a surviving stellar remnant at its center, nicknamed a “zombie star.”
Mashable Light Speed
Pa 30 is considered the only known remnant of a Type Iax supernova in the Milky Way. These are relatively low-energy, incomplete stellar explosions that can leave a surviving star behind. A standard Type Ia supernova, by comparison, destroys the exploding white dwarf.
The Gemini North telescope’s laser guide star beams up into the atmosphere. The laser guide star is used to measure turbulence in the Earth’s atmosphere so the telescope can correct for it and achieve clear images of the night sky.
Credit: International Gemini Observatory/NSF NOIRLab
What the new image reveals
The Gemini observations reveal roughly 10 times as many filamentary features as earlier images showed. They also expose the chains of gas knots that make up those filaments, giving researchers new clues about how the debris took shape.
According to NOIRLab, differences in temperature or density in the material surrounding the star may have helped shape the expanding ejecta. Exactly how those remarkably uniform knots formed remains a question for researchers to investigate.
The team also found that the surviving star sits almost exactly at the remnant’s center. An uneven explosion can give a surviving star a “kick,” sending it away from the center. Pa 30’s configuration indicates that its star received no large sideways kick, offering another clue about the blast.
Researchers hope to use Pa 30’s distinctive features to help find similar remnants in our galaxy and nearby ones. For now, this medieval light show is still giving astronomers something new to look at.
