Spitzer Space Telescope - General Observer Proposal #60055


Direct Observation of Circumstellar Clumps in High Mass X-Ray Binaries

Principal Investigator: Gordon Sarty
           Institution: University of Saskatchewan

     Technical Contact: Gordon Sarty, University of Saskatchewan

Co-Investigators: 
Zoltan Balog, University of Arizona                                   
Laszlo Kiss, University of Sydney                                     
Kinwah Wu, University College London                                  

Science Category: compact objects 
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 12.5 

Abstract:
The direct observation of clumpy circumstellar material in high mass X-ray
binaries (HMXBs) is proposed. We propose to observe the two HMXBs V420 Aur and
LS 5039, based on our optical data obtained over the past four years. With
precision time- series photometry from the post-cryo IRAC instrument we expect
the following scientific return: (i) Characterization of the size and
distribution of circumstellar clumpy material as derived from modeling the light
curve variations produced as the clumps disappear behind the star. (ii)
Characterization of the temperature of the clumps as inferred from the 3.6 - 4.5
micrometer color of the clumps disappearing behing the primary star. (iii)
Serendipitous observation of clumpy accretion events produced as clumps heat up
on their way to accretion on the neutron star or black hole.