Introduction

In a groundbreaking study, researchers have unveiled astonishing insights about a strange phenomenon known as the "zombie star," hidden within the remnants of a supernova that brightened Earth's skies nearly 843 years ago. An unprecedented animated map has shown that the remnants of this stellar explosion are asymmetrical and continue to expand at an astonishing rate.

Historical Context

Back in 1181, stargazers in China and Japan documented a new star appearing near the constellation Cassiopeia. This "guest star" was visible for several months, from August 1181 until February 1182. Today, astronomers recognize this phenomenon as a significant supernova event, designated as SN 1181, though the mystery of its origin persisted until relatively recently. In 2021, scientists pinpointed the supernova's source to the nebula Pa 30, a colossal gas cloud even larger than our solar system.

The Zombie Star

At the heart of Pa 30 lies a white dwarf star—a dense remnant of the original star that exploded. This stellar corpse radiates flame at around 360,000 degrees Fahrenheit (200,000 degrees Celsius), placing it among the hottest stars known to humanity. Unlike typical supernova remnants that are torn apart entirely, this remarkable "zombie star" has somehow survived the cataclysmic explosion, a rarity in astronomical observations.

Recent Discoveries

Recent findings, published on October 24 in *The Astrophysical Journal Letters*, utilized the Keck Cosmic Web Imager (KCWI), stationed atop Mauna Kea in Hawaii. This device has generated a detailed new map of Pa 30, unveiling extensive filaments that the researchers liken to "the petals of a dandelion" that radiate from the white dwarf to the nebula's outer reaches.

3D Movie of Pa 30

By studying the shifting light from Pa 30 over the years, astronomers have been able to trace its evolving shape, resulting in a mini "3D movie" that chronicles the nebula's history—a first of its kind for a supernova remnant. One significant discovery from this animation is the nebula's rapid expansion at about 2.2 million mph (3.5 million km/h). This speed mirrors that of the debris ejected during the supernova event, indicating that the expelled material has maintained its velocity since the initial explosion. Tim Cunningham, the lead author from the Harvard and Smithsonian Center for Astrophysics, emphasized that this added proof cinches the guest star's origin to the dramatic events of 1181.

Asymmetry and Ongoing Research

In addition to the discoveries regarding speed and transformation, the new map highlights an unexpected asymmetry in Pa 30 compared to other known supernova remnants. The cause of this irregularity remains a mystery, prompting questions about how the original supernova led to such an unusual structure.

Conclusion

This research not only enhances our understanding of the cosmic events that create supernovae but also raises intriguing questions about the life cycles of stars and the complex mechanisms that govern their explosive deaths. As scientists continue to delve into the mysteries of the universe, this “zombie star” serves as a captivating reminder of the incredible phenomena that exist beyond our planet.