The story
The Book of the Later Han reports that in the tenth month of the second year of the Zhongping reign, a guest star appeared in the Southern Gate, a group of stars in the region of Centaurus. Chinese astronomers called new stars that stayed in one place guest stars, in contrast to broom stars, which moved. The record gives the date as December 185 CE, and says the star faded away after about eight months.
A new star that lasts months without moving points to a supernova, the explosion of a star. In 2006 and later, X-ray astronomers argued that the remnant RCW 86, about 8,000 light years away, has an age close to 1,800 years, which matches the record. Not everyone accepts the link, since the entry is short and a bright comet without a tail is not ruled out. If the match is right, this is the oldest supernova known from a written record.
Why it mattered
- Gave astronomers the oldest likely supernova match between a written record and a remnant.
- Let researchers test remnant ages against historical dates, a method used for SN 1006 and SN 1054.
- Showed the value of the Chinese court's careful sky logs for modern astrophysics.
Sources
- RCW 86 Chandra X-ray Center
- 'Supernova' 185 is really a nova plus Comet P/Swift-Tuttle (Bradley Schaefer, 1995) Louisiana State University repository
- The First Supernova Smithsonian Magazine
Contested history
Consensus: Most astronomers think the guest star of 185 was a supernova linked to the remnant RCW 86, though the case rests on a single short record.
- RCW 86 Chandra X-ray Center
- The First Supernova Smithsonian Magazine
- 'Supernova' 185 is really a nova plus Comet P/Swift-Tuttle (Bradley Schaefer, 1995) Louisiana State University repository
Community notes
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