Cool Stars 14 - Submitted Abstract # 67
This version created on 05 October 2006

Far Infrared Properties of M Dwarfs


Thomas N. Gautier, NASA JPL/Cal Tech
George H. Rieke, Steward Observatpry, University of Arizona
John Stansberry, Steward Observatpry, University of Arizona
Geoffrey C. Bryden, NASA JPL/Cal Tech
Karl R. Stapelfeldt, NASA JPL/Cal Tech
Michael W. Werner, NASA JPL/Cal Tech
Charles A. Beichman, NASA JPL/Cal Tech
Christine Chen, NOAO
Kate Su, Steward Observatory, University of Arizona
David Trilling, Steward Observatory, University of Arizona
Brian M. Patten, Harvard-Smithsonian Center for Astrophysics
Thomas L. Roellig, NASA Ames Research Center

Mid- and far-infrared properties of nearby M dwarfs are derived from
Spitzer/MIPS measurements of a sample of 62 stars at 24 um, with
subsamples of 41 and 20  stars observed at 70  um and 160  um
respectively.  We compare the results with current models of M star
photospheres and look for indications of circumstellar dust in the
form of significant deviations of K-[24 um] colors and 70  um / 24 um
flux ratios from the average M star values.  At 24 um, all 62 of the
targets were detected;  70  um detections were achieved for 20
targets in the subsample observed;  and no detections were seen in the
160  um subsample.  No clear far-infrared excesses were detected in
our sample.  The average far infrared excess relative to the
photospheric emission of the M stars is at least four times smaller
than the similar average for a sample of solar-type stars.  However,
this limit allows the average fractional infrared luminosity in the
M-star sample to be similar to that for more massive stars.

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