RCW 86: Historical Supernova Remnant

RCW 86: Historical Supernova RemnantIn 185 AD,Chineseastronomers recorded the appearance ofa new star in the Nanmen asterism -a part of the sky identifiedwith Alpha and Beta Centauri on modern star charts.The new star was visible for months and isthought to be the earliestrecorded supernova.This multiwavelengthcomposite image from orbiting telescopes of the 21st century,XMM-Newton and Chandra in X-rays, and Spitzer and WISE in infrared,showsupernova remnant RCW 86,understood to be the remnant of thatstellar explosion.The false-color viewshows interstellar gas heated by the expanding supernova shock waveat X-ray energies (blue and green) and interstellar dust radiating atcooler temperatures in infrared light (yellow and red).An abundance of the element iron and lack of a neutron star or pulsarin the remnant suggest that the original supernova was Type Ia.Type Iasupernovae are thermonuclear explosions thatdestroya white dwarf star as it accretes material from a companionin a binary star system.Shock velocitiesmeasured inthe X-ray emitting shell and infrared dust temperatures indicate thatthe remnant is expanding extremely rapidly into a remarkablelow density bubble created before the explosion by the white dwarf system.Near the plane of our Milky Way Galaxy,RCW 86 is about 8,200 light-years away and has an estimated radiusof 50 light-years.

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