The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in
  the Large Magellanic Cloud. Point source classification I
  We present the classification of 197 point sources observed with the Infrared
Spectrograph in the SAGE-Spec Legacy program on the Spitzer Space Telescope. We
introduce a decision-tree method of object classification based on infrared
spectral features, continuum and spectral energy distribution shape, bolometric
luminosity, cluster membership, and variability information, which is used to
classify the SAGE-Spec sample of point sources. The decision tree has a broad
application to mid-infrared spectroscopic surveys, where supporting photometry
and variability information are available. We use these classifications to make
deductions about the stellar populations of the Large Magellanic Cloud and the
success of photometric classification methods. We find 90 asymptotic giant
branch (AGB) stars, 29 young stellar objects, 23 post-AGB objects, 19 red
supergiants, eight stellar photospheres, seven background galaxies, seven
planetary nebulae, two HII regions and 12 other objects, seven of which remain
unclassified.
