Spitzer Space Telescope - General Observer Proposal #50530


Confirming a second Helix-like cool debris disk

Principal Investigator: Matt  Burleigh
           Institution: University of Leicester

     Technical Contact: Matt  Burleigh, University of Leicester

Co-Investigators: 
Carolyn Brinkworth, Spitzer Science Center                            
Donald Hoard, Spitzer Science Center                                  
Stefanie Wachter, Spitzer Science Center                              
Paul Steele, University of Leicester                                  
Ralf Napiwotzki, University of Hertfordshire, UK                      
Hans Zinnecker, Astrophysikalisches Institut Potsdam, Germany         
Paul Dobbie, Anglo-Australian Observatory                             

Science Category: circumstellar/debris disks 
 Observing Modes: MipsPhot 
  Hours Approved: 0.4 

Abstract:
An IRAC observation of the central star of the old planetary nebula DeHt5
(WD2218+706) reveals excess emission at 8 microns, above that expected from the
white dwarf alone. We can match this emission with a 100K blackbody, and it
bares striking similarity to the so-far unique 100K excess emission observed for
the central star of the Helix nebula (Su et al. 2007). MIPS photometry of the
Helix has revealed the presence of a large, cool debris disk between 30-150AU
from the central star, which may be the result of collisions in a Kuiper-belt
during post-main sequence evolution. We will obtain MIPS photometry of
WD2218+706 to confirm the excess emission, better constrain its temperature,
mass and geometry, and compare it to the Helix. The confirmation of a second
Helix-like disk around this older white dwarf would also enable us to begin
investigation of the evolution of these debris disks with time.