RCW 86


Click on the image for a larger version

RCW 86 is a Supernova Remnant (SNR) located in the Southern constellation of Circinus. This one is not any SNR. Its explosion was witnessed, in the year 185 (CE), by Chinese astronomers, making it the first supernova recorded in History. Until recently, astronomers were puzzled about how could have this SNR have expanded so much in such a brief period of time. The clue came by studying it under the x-ray light. The parent white dwarf had, previous to the explosion, cleared its surroundings of any other gas or dust, carving a kind of a “cave”. This way, when it exploded, there was nothing to brake the expansion of its gases.

The SNR images show clearly that these objects expel two very distinct gases: the Hydrogen clouds, emitting at the Halpha line (Red), and the Oxygen clouds, emitting at the OIII line (greenish-blue). Oxygen is generated through the CNO process inside the stars.


RCW 86. © NASA/CXC/SAO & ESA (for the X-ray) and NASA/JPL-Caltech/B. Williams (NCSU) for the Infrared.

This image was taken by combining the data from four space telescopes, the Chandra X-ray telescope, the XMM-Newton X-ray telescope, together with the Spitzer Space Telescope and WISE, Wide-Field Infrared Survey Explorer. This image shows a “bright” green-bluish area inside the “croissant” shape, that is not captured in the first picture, because it is just a few dozen degrees above absolute zero, and therefore visible only in deep infrared.

Additional Information


Name(s): RCW 86. G 315.2-2.3

Type: Supernova Remnant (SNR)

RA:  14h 40m 38s

Dec: -62º 37’ 12”

Constellation: Circunus

Size (arcmin): 12×12


Distance: 8,000 ly


Date: 2016-03-21 thru 2016-04-02

Location: iTelescope.net, SSO near Coonabarabran, NSW Australia

Size (arcmin): 32×32

Telescope: Planewave CDK 20” f/6.8

Camera: SBIG STX16803 (4096x4096pix)

Guiding: Astrodon MonsterMOAG off-axis guider

Total exposure: 22.5 hours (Ha: 12.5 hs; OIII: 8.5 hs; RGB: 1.5 hs)

Processing: CCDStack, Photoshop CC 2015.5

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