© K. Ilkiewicz and J. MikolajewskaThis image shows the ejected shell of the recovered Nova Scorpii 1437. The red tick marks show the current location of the source and the red plus sign marks the location of the shell center in 1437.
Astronomers and historians pinpoint the source of a 15th-century classical nova. It's currently regathering strength.In 1437, Korean royal astronomers observed a new star appearing in the constellation Scorpius. "A guest star began to be seen between the second and third stars of Wei," they wrote in the
Sejong Sillok, a chronicle of the reign of King Sejong who ruled Korea from 1418 to 1464. The star faded from sight after 14 days.
What the puzzled subjects of King Sejong witnessed was a classical nova - the outburst of a
white dwarf in a close binary system when it collects sufficient hydrogen from its companion star.
In this scenario a white dwarf, normally hydrogen-poor, accumulates fresh gas on its surface until the bottom layers become deep and hot enough that hydrogen atoms begin to fuse. A runaway thermonuclear reaction ensues, turning the dwarf's thin surface layer into a shell-shaped hydrogen bomb.
But little is known about what happens to the binary system centuries after the white dwarf throws its tantrum. Astronomers think the system remains relatively unharmed and the gas transfer resumes, setting things in motion for another catastrophic event. Indeed, "recurrent novae" re-explode on observably short timescales.
A team led by Michael Shara (American Museum of Natural History) with help from Richard Stephenson (Durham University), a historian specializing in Asian astronomical records, followed the indications from the
Sejong Sillok to look for the stellar system responsible for the guest star, now called Nova Scorpii 1437. "It was the best-located classical nova in over 2,000 years of records by Chinese, Korean and Japanese astronomers," Shara says. "We expected it to be faint, so a fairly precise location was essential if we were to have any realistic chance of recovering it."
Comment: Some other transient luminous events (TLEs) so far this year include:
July 2017: Huge red sprite captured over Austria
June 2017: Red jellyfish sprites with halo of light captured over Austria
April 2017: Rare ELVE and red sprites captured in Czech Republic and 6 'gigantic jets' (ionospheric lightning) were photographed in Western Australia.
March 2017: A huge blue jet was observed over Brazil.
See also: Electric universe: Lightning strength and frequency increasing
The Electric Universe model is clearly explained, with a lot more relevant information, in the book Earth Changes and the Human Cosmic Connection by Pierre Lescaudron and Laura Knight-Jadczyk.