been likened to an "apple on a stick." By June 13, a second tail created by dust from the comet, was also visible, sharing the same green hue of the coma. The green colors in the coma are caused by the presence of cyanogen and diatomic carbon, while bluish hues in the ion tail are produced by positively charged carbon monoxide and carbon dioxide ions. References External links NASA Jet Propulsion Laboratory Small-Body Database Browser on C/2009 R1 NASA Astronomy Picture of the Day: June 17, 2010, Comet McNaught Passes NGC 1245 June 7, 2010, Comet McNaught Becoming Visible to the Unaided Eye Comet C/2009 R1 (McNaught) in Andromeda Comet C/2009 R1 (McNaught) - Animation & Images (disconnection event 26 May 2010 / Remanzacco Observatory) Non-periodic comets 20090909