Now, using NASA’s <a href="http://www.spitzer.caltech.edu/" target="_blank" class="news_link" title="Spitzer Space Telescope">Spitzer Space Telescope</a> and <a href="http://wise.ssl.berkeley.edu/" target="_blank" class="news_link" title="Wide-field Infrared Survey Explorer">Wide-field Infrared Survey Explorer</a> (WISE), scientists have learned even more of the supernova remnant’s secrets.


“It’s two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we’ve been able to finally pinpoint the cause,” says Brian J. Williams, an astronomer at North Carolina State University in Raleigh and lead author of the <a href="http://arxiv.org/abs/1108.1207" target="_blank" class="news_link" title="RCW 86: A Type Ia Supernova in a Wind-Blown Bubble">study</a> detailing the new findings.


What the Chinese astronomers observed so many years ago was a <a href="http://en.wikipedia.org/wiki/Type_Ia_supernova" class="news_link" title="Type Ia supernova" target="_blank">“Type Ia” supernova</a>, which was created by the relatively peaceful death of a star – much like our own sun – which then shrank into a dense star called a <a href="http://en.wikipedia.org/wiki/White_dwarf" target="_blank" class="news_link" title="white dwarf">white dwarf</a>. It’s thought that this white dwarf, after siphoning matter or fuel from a nearby star, later blew up in a supernova.


We’ve learned, for the first time, that a white dwarf can create a cavity around it before blowing up into a Type Ia event. A cavity would explain why the remains of RCW 86 are so big. When the explosion occurred, the ejected material would have traveled, unimpeded by gas and dust, spreading out quickly.



Source: Voice of America