NASA’s Chandra X-ray Observatory illuminates 800-Year-Old Explosion

NASA’s Chandra X-ray Observatory is playing detective.

The space telescope is helping scientists investigate the remnants of a supernova first observed in 1181.

In a new blog post on NASA’s website, the space agency revealed an impressive composite image of the prime candidate in that search. The new image, made up of observations by Chandra and other observatories, sheds light on an incredibly rare type of supernova.

Chandra investigates SN 1181

In the year 1181, observers witnessed a rare supernova explosion in the night sky. Records show that it was visible for 185 days. At the time, those observing the supernova, now called SN 1181, described it as a “star” in the constellation Cassiopeia. It shone as bright as Saturn before disappearing.

Scientists have since looked for the supernova’s remnant using modern instruments. For a while, scientists believed the supernova could have turned into the nebula surrounding a pulsar named 3C 58. However, closer observations revealed that the pulsar had been around before 1181.

More recently, scientists turned their attention to a nearly circular nebula called Pa 30. Now, NASA has shared new images of Pa 30 captured by Chandra and other observatories.

The composite image (shown at the top of the page) combined data across the electromagnetic spectrum. It presents an impressive new view of the supernova remnant, likely the same one seen in the night sky over 800 years ago.

Observatories unite to form Pa 30 composite

X-ray observations by the European Space Agency (ESA) XMN-Newton space telescope show up in blue in the composite image. They help to show the full extent of the nebula. NASA’s Chandra X-ray Observatory observations, meanwhile, are visible in cyan. They highlight the nebula’s central source.

The red and pink in the image come from infrared light observations collected by NASA’s Wide-field Infrared Space Explorer. The ground-based Hiltner 2.4 m telescope at the MDM Observatory in Arizona, USA, captured the radial structure of the nebula, which appears in green.

Scientists studied this composite in detail and they believe the remnant was formed in a thermonuclear explosion. To be precise, they think it was formed by a special type of supernova called a sub-luminous Type lax event.

This occurs when two white dwarf stars merge. Typically, when that happens, no remnant is formed. However, incomplete explosions create a kind of “zombie” star, as in the case of Pa 30.

Pa 30 is one of the hottest stars in the Milky Way. Scientists have recorded its temperature sitting at around 200,000 degrees Celsius. It also has a stellar wind that travels at up to 16,000 km/h.

The new composite image will help scientists better understand this incredibly rare supernova. What’s more, it could help determine once and for all, whether Pa 30 is truly the remnant of SN 1181.