The debris of an exploded star – known as supernova remnant 1E 0102.2-7219, or E0102 for short – was taken from NASA’s Chandra X-ray Observatory. Its name is derived from its cataloged placement or coordinates in the celestial sphere. E0102 is located about 200,000 light years away in the Small Magellanic Cloud, one of the nearest galaxies to the Milky Way. It was created when a star that was much more massive than the Sun exploded, an event that would have been visible from the Southern Hemisphere of the Earth over 1000 years ago.
Chandra first observed E0102 shortly after its launch in 1999. New X-ray data have now been used to create this spectacular image, where the lowest-energy X-rays are colored orange, the intermediate range of X-rays is cyan, and the highest-energy X-rays Chandra detected are blue, also revealing foreground stars in the field. The composition and thus, the colouring of the diffuse remnant is due to the presence of very large quantities of oxygen compared to hydrogen. One explanation for the abundance of oxygen in the SNR is that the parent star was very large and old, and had blown away most its hydrogen as stellar wind before it exploded. It is surmised that the progenitor star that caused the supernova explosion may have been a Wolf-Rayet. These stars, which can be upward of 20 times the mass of the sun and tens of thousands times more luminous, are famous for having a strong stellar wind throughout their lifetime. This stellar wind carried off material from the outer-most shells of the star (the hydrogen and helium shells), leaving the next most abundant element, oxygen, as a visible signature after the star exploded as a supernova.
Analysis of the Chandra spectrum gives astronomers new information about the geometry of the remnant, with implications for the nature of the explosion. The spectrum – which precisely separates X-rays of different energies – shows some material is moving away from Earth and some is moving toward us. When the material is moving away, its light is shifted toward the red end of the spectrum due to the so-called Doppler effect. Alternatively, when material is moving toward us, the light is bluer because of the same effect. A clear separation was detected between the red-shifted and blue-shifted light, leading astronomers to think that the appearance of E0102 is best explained by a model in which the ejecta is shaped like a cylinder that is being viewed almost exactly end-on. The smaller red and blue cylinders represent faster moving material closer to the cylinder axis.
Credits: Chandra X-Ray Observatory, Hubble.