Supernova Remnants: Vela and Puppis
Two supernova remnants are clearly seen in this image. The larger is the Vela SNR which covers most of the field. The smaller is the Puppis SNR which is superimposed on the Vela SNR and is the bright enhancement in the upper right of the image. Vela, at a distance of roughly 1,500 light years is relatively nearby. It is about 11,000 years old and has a diameter of 230 light years. ROSAT observations showed for the first time that Vela is roughly circular; previously only the brighter regions in the upper and left hand sides of the figure had been detected. Puppis is about four times farther from the Sun than Vela.
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