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Astronomy Picture of the Day - RCW 86: Historical Supernova Remnant
NASA ^ | 24 Jul, 2026 | Image Credit & Copyright: David Cowland

Posted on 07/24/2026 12:01:00 PM PDT by MtnClimber

Explanation: In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with part of the southern constellation Centaurus on modern star charts. In fact, the new star was reported to be visible to the naked eye for months before it faded from view, and is now thought to be the earliest recorded supernova. In this 21st century telescopic image, the wispy outlines of a faint emission nebula recognized as the remnant of that historical stellar explosion can be traced against a starry background. The ragged but roughly circular extent of the nebula, cataloged as RCW 86, represents interstellar gas ionized by the supernova's still expanding shock wave. Space-based images indicate an abundance of the element iron in RCW 86 and the absence of a neutron star or pulsar within the remnant, suggesting that the original supernova was Type Ia. Unlike the core collapse supernova explosion of a massive star, a Type Ia supernova is a thermonuclear detonation on a white dwarf star that has accreted material from its companion in a binary star system. Near the plane of our Milky Way galaxy and larger than the full moon on the sky this supernova remnant is too faint to be seen by eye though. RCW 86 is some 8,000 light-years distant and around 100 light-years across.


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; nasa
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1 posted on 07/24/2026 12:01:00 PM PDT by MtnClimber
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2 posted on 07/24/2026 12:01:25 PM PDT by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber

Wow.


3 posted on 07/24/2026 12:01:35 PM PDT by No name given ( Anonymous is who you’ll know me as )
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To: 21stCenturion; 21twelve; 4everontheRight; A Navy Vet; A_perfect_lady; abb; AFB-XYZ; AFPhys; ...
Pinging the APOD list

🪐 🌟 🌌 🍔

4 posted on 07/24/2026 12:02:02 PM PDT by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber

bttt


5 posted on 07/24/2026 12:07:04 PM PDT by BenLurkin (The above is not a statement of fact. It is opinion or satire. Or both.)
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