American Museum of Natural History | 2017 Aug 30
On a cold March night in Seoul almost 600 years ago, Korean astrologers spotted a bright new star in the tail of the constellation Scorpius. It was seen for just 14 days before fading from view. From these ancient records, modern astronomers determined that what the Royal Imperial Astrologers saw was a nova explosion, but they had been unable to find the binary star system that caused it—until now. A new study published today by the journal Nature pinpoints the location of the old nova, which now undergoes smaller-scale “dwarf nova” eruptions. The work supports that idea that novae go through a very long-term life cycle after erupting, fading to obscurity for thousands of years, and then building back up to become full-fledged novae once more.
“This is the first nova that’s ever been recovered with certainty based on the Chinese, Korean, and Japanese records of almost 2,500 years,” said the study’s lead author Michael Shara, a curator in the American Museum of Natural History’s Department of Astrophysics.
A nova is a colossal hydrogen bomb produced in a binary system where a star like our Sun is being cannibalized by a white dwarf—a dead star. It takes about 100,000 years for the white dwarf to build up a critical layer of hydrogen that it steals from the sun-like star, and when it does, it blows the envelope off, producing a burst of light that makes the star up to 300,000 times brighter than the sun for anywhere from a few days to a few months.
For years, Shara has tried to pinpoint the location of the binary star that produced the nova eruption in 1437, along with Durham University’s Richard Stephenson, a historian of ancient Asian astronomical records, and Liverpool John Moores University astrophysicist Mike Bode. Recently, they expanded the search field and found the ejected shell of the classical nova. They confirmed the finding with another kind of historical record: a photographic plate from 1923 taken at the Harvard Observatory station in Peru and now available online as part of the Digitizing a Sky Century at Harvard (DASCH) project. ...
Proper-motion age dating of the progeny of Nova Scorpii AD 1437 - M. M. Shara et al
- Nature 548(7669):558 (31 Aug 2017) DOI: 10.1038/nature23644
- arXiv.org > astro-ph > arXiv:1704.00086 > 31 Mar 2017