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posted by takyon on Thursday August 31 2017, @12:13AM   Printer-friendly
from the now-where-did-I-put-my-astrophysics? dept.

Seems that astronomers have located the nova remnant of a star that exploded some 600 years ago.

According to Space.com:

After decades of hunting, astronomers have tracked down the origin of a nova first recorded by Korean royal astrologers nearly 600 years ago.

Evidently, Korean records are slightly different than more recent Western ones:

When the researchers first looked about three decades ago where the records seemed to say the nova was, they could not find it: "It turns out we were looking in the wrong place," Shara said. "When it comes to analyzing ancient records, it can be a challenge interpreting them correctly."

Of course, what is more interesting, is that a Nova Stella, a new star that is clearly visible, was recorded in Korea, but not in Europe. A similar situation exists with the "guest star" that resulted in the Crab Nebula, which exploded in 1054, and was recorded by Chinese astronomers. This was a supernova, and the star was so bright it could be seen during daylight, but no mention of it exists in European records.

Aristotelian doctrine, and that of the Church, was that the Heavens were unchanging, so comets were very disturbing, and new stars so unthinkable that they could not be seen? And it was Tycho Brahe and Kepler's discovery of Stella Novae that set the stage for modern astronomy.

Other coverage, including info on "dwarf nova" erupting at the same system.

Proper-motion age dating of the progeny of Nova Scorpii AD 1437 (DOI: 10.1038/nature23644) (DX)


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  • (Score: 2, Informative) by aristarchus on Thursday August 31 2017, @05:08AM

    by aristarchus (2645) on Thursday August 31 2017, @05:08AM (#561967) Journal

    ] was visible in the night sky for about 2 years.

    This is suspect. Let me explain why. "Nova" means "new", not quite like the Chevrolet called "No Va", which in Spanish means "doesn't go". Stars explode, and various stars explode in various ways. Not enough time to go into detail, but stars start off as balls of hydrogen, where there is enough gravitational attraction to bring it all together, and more importantly, begin a process of nuclear fusion, where the hydrogen it fused into helium, with a release of some extra energy (light). Stars keep combining elements by fusion, helium into lithium, lithium into, OK, I forget, but the point is, the more they convert less dense elements into more dense, the less energy they have to release, and so they can end up being "carbon stars", which burn red, or worse, iron stars, because this is the point at which further consolidation becomes much more difficult. And they collapse and then explode.
          So, some stars explode, or, rather like TMB, the implode and then rebound in an explosion, which produces a shell of gas cast off of the star, but still irradiated or illuminated by what remains of the star. We call these "planetary nebulae". But there are others, like the binary systems theorized to produce "super" nova, or much larger explosions, from a binary star system. The idea is that there is standard version of these, the type One A (Ia) supernova, that has a rather constant output and so allows astronomers to estimate distance. But the important thing is that nova and supernova only last for weeks, and then they fade. Most of the recent Super Novae (SN) have been detected in other galaxies, but they too fade rather quickly. Remnants remain, however, in nova that have occurred within the Milky Way galaxy itself.

          The point is that a nova, or a supernova, would be visible for a matter of weeks, not years. A supernova within our galaxy may well be bright enought to observe during daylight, whereas those that occur in other galaxies would remain telescope visible objects, like SN2014j [wikipedia.org]. This is why the Chinese or Korean observers called them "guest stars", since they did not stay.

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