Student discovers Stellar Chamaeleon that had the Astronomers Fooled for Years

High angular resolution images of CW Leo spanning more than eight years. Credit: Paul Stewart and Peter Tuthill, University of Sydney.

It is the brightest infrared star in the Northern sky, but a student has found that astronomers have been mistakenly interpreting the dust in the environment of a famous star that lies 450 light years from Earth. The star CW Leo aka IRC+10216, would be the second brightest star in the sky if our eyes could see infrared light. Images of its circumstellar environment released today reveal substantial evolution occurring over a span of more than 8 years, with none of the previously identified bright spots in fact containing the star, which is now believed to be buried in its own dust.

Graduate student Paul Stewart has reconstructed images from 2000 to 2008 – which are more akin to a changing inkblot pattern than a star – including high angular resolution images from stellar occultations by the rings of Saturn observed with the Cassini spacecraft. Professor Tuthill said the new images made it clear that the red giant’s clumps and plumes of hot dust being ejected had confused generations of astronomers, who interpreted them as key structural elements to the system.

CW Leo is one of the most extensively studied evolved stars, believed to be on the cusp of planetary nebula formation – the process ending the red giant’s life is potentially already under way. The new work demonstrated that none of the previously identified structures in IRC+10216’s circumstellar environment were persistent and therefore could not be representative of the alignment or position of the star.

“In trying to find an underlying structure to the clumps and blobs, we have seen little more than our own preconceptions reflected back at us — like a giant celestial Rorschach Ink Blot Test,” Professor Tuthill said. Whatever future study will reveal, it is perhaps the observation of this star that is the end in itself, Mr Stewart said: “The real excitement is the extreme physics – CW Leo is a swollen luminous giant poised at the most self-destructive phase of its existence. “It is literally tearing itself apart under its own glare, hurling dense clouds of dust and gas out into the galaxy; dying amidst its own glorious final fireworks display.”
http://sydney.edu.au/news-opinion/news/2015/12/04/student-discovers-stellar-chamaeleon-had-astronomers-fooled-for-.html