Instrument, Data Reduction, and Preliminary Results DU Graduate Student Colloquium Kathy Geise Image Courtesy NASA/JPL-Caltech

Why Dust?  Most elements in the Universe came from AGB stars  Pre-solar grains found in meteorites are of AGB origin  Hundreds of TONS of dust rain down on Earth every day  The Universe is a dusty place  Most elements in the Universe came from AGB stars  Pre-solar grains found in meteorites are of AGB origin  Hundreds of TONS of dust rain down on Earth every day  The Universe is a dusty place

NOW YOU SEE DUST, NOW YOU DON’T  Infrared light can travel through dust while optical light is blocked by it  The dust making up the pillars in this image has been warmed by stars and glows in the infrared making it visible

Spitzer Space Telescope  Launched August 25, 2003  Earth trailing, Heliocentric orbit  Transition to warm mission  Three instruments onboard  Infrared Array Camera (IRAC) (  m)  Infrared Spectrograph (IRS) (  m)  Multiband Imaging Photometer (MIPS) (24, 70, 160  m) Image Courtesy NASA/JPL-Caltech

MIPS 70  m  Gallium-doped germanium photodetector  Time dependant response  Spontaneous spiking  Hook  Cosmic ray hits  Built in stimulators Image Courtesy NASA/JPL-Caltech

Cold Dust Emission Image Courtesy NASA/JPL-Caltech

Source: U Hya Previous Current DSS/1 MIPS 70  m overlay IRAS 60  m

 Mosaic image

 AOR overlay

 Stim flash

 False color

 Dither

 Stim flash

Input files:  Basic Calibrated Data (BCD)  bmask (bad sectors)  bunc (uncertainty) Data Reduction Output files:  Background subtracted intermediate step

Data Reduction Remove:  Cosmic Ray Hits (radhits)  Outliers  Background sky emission Create mosaic Extract emission data U Hya 70  m

Preliminary Results Current Values  Distance 208 pc  Shell diameter 240” (0.4 pc)  Shell velocity 7 km/s (Knapp 1998)  Dynamical age of shell 30,000 years  Shell mass 3x solar masses

Preliminary Results Current Values  Distance 126 pc  Shell diameter 300” (0.23 pc)  Shell velocity 12 km/s (Knapp 1998)  Dynamical age of shell 20,000 years  Shell mass 9.6x solar masses.

Preliminary Results Current Values  Distance 321 pc  Shell diameter 500” (0.80 pc)  Shell velocity 8 km/s (Knapp 1998)  Dynamical age of shell 47,000 years  Shell mass 5x solar masses.

Future Work  Continue data reduction 37 sources in data set  Improve sky background removal  Create radial profiles  Compare observed mass loss against theory  Model circumstellar dust shells

Acknowledgements Dr. Toshiya Ueta Principal Investigator Spitzer Project ID This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

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