Download - The Universe in the Infrared
The Universe in the Infrared
Finding stars with planets using the Spitzer Infrared Telescope
Funded by NASA’s Spitzer Science Center
Images courtesy NASA/JPL - Caltech
Pilachowski / August 2005
The Universe in the Infrared
Slide 2
Background Science
• Rocky/icy “debris disk” remains after a star is formed– Similar to our asteroid belt
or Kuiper belt
• Planets cause debris to collide
• Dust!• Dust glows in the mid-
infrared
Pilachowski / August 2005
The Universe in the Infrared
Slide 3
Hunting for Planets in IC 4665
• IC 4665 is a star cluster– hundreds of stars– distance of 352 pc– size about 5 pc– age 50-100 Myr
Pilachowski / August 2005
The Universe in the Infrared
Slide 4
Spitzer Observations of 9 Stars
• Individual stars observed with Spitzer
• 5’ x 5’ squares centered on target stars
• visual and near-IR brightness measurements available from the literature
Pilachowski / August 2005
The Universe in the Infrared
Slide 5
Flux Density vs. Wavelength
Flux Density Measurements in mJy for IC 4665 Targets
2MASS Infrared Fluxes
Waveband: B (blue) V (visual) I (near IR) J H K
Wavelength (nm): 440 550 970 1235 1662 2159
Star ID
Prosser 7 586 675 551 517 364 246
Prosser 11 839 882 615 571 385 252
Prosser 18 780 890 693 642 442 299
Prosser 37 217 257 207 189 136 89.9
Prosser 40 547 272 211
Prosser 45 1920 1970 1110 770 478
Prosser 46 1060 1080 732 622 387 274
Prosser 48 256 303 236 234 160 108
Prosser 54 398 438 332 294 203 143
Sources:
BVI Photometry: Prosser, C. F. 1993, Astronomical Journal, 105, 1441
2MASS IR Photometry: This activity makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation (http://www.ipac.caltech.edu/2mass/).
Pilachowski / August 2005
The Universe in the Infrared
Slide 6
Black Body Curves
Pilachowski / August 2005
The Universe in the Infrared
Slide 7
Finding Planets in IC 4665
• Plot flux densities at B, V, I, J, H, K• Estimate 24,000 nm flux density by
extrapolating black body curve• Measure 24,000 nm flux density from
Spitzer images• Do any of the stars show excess flux
at 24,000 nm?
Pilachowski / August 2005
The Universe in the Infrared
Slide 8
Measuring fluxes
• http://www.phys.vt.edu/~jhs/SIP/
• on-line image processing
• Spitzer images on CD in the notebook