Classification of 2.4-45.2 micron spectra from the ISO Short Wavelength Spectrometer

K.E. Kraemer (Air Force Research Lab., Boston Univ.), G.C. Sloan (Boston College, Cornell), S.D. Price (Air Force Research Lab.), H.J. Walker (Rutherford Appleton Lab.)

2002, ApJS, 140, 389

The Infrared Space Observatory observed over 900 objects with the Short Wavelength Spectrometer in full-grating-scan mode (2.4-45.2 µm). We have developed a comprehensive system of spectral classification using these data. Sources are assigned to groups based on the overall shape of the spectral energy distribution (SED). The groups include naked stars, dusty stars, warm dust shells, cool dust shells, very red sources, and sources with emission lines but no detected continuum. These groups are further divided into subgroups based on spectral features that shape the SED such as carbon-rich dust emission, silicate absorption, ice absorption, and fine-structure or recombination lines. Caveats regarding the data and data reduction and biases intrinsic to the database are discussed. We also examine how the subgroups relate to the evolution of sources to and from the main sequence and how this classification scheme relates to previous systems.

Downloadable figures in postscript and PDF format:

Fig. 1 PS (466) PDF (294)

Fig. 2 PS (700) PDF (432)

Fig. 3 PS (474) PDF (313)

Fig. 4a PS (666) PDF (405)

Fig. 4b PS (657) PDF (379)

Fig. 4c PS (324) PDF (216)

Fig. 5a PS (548) PDF (334)

Fig. 5b PS (437) PDF (284)

Fig. 6 PS (659) PDF (417)

Figure N illustrates spectra from Group N.

• Group 1: Naked stars
• Group 2: Stars with dust
• Group 3: Warm dust sources
• Group 4: Cool dust sources
• Group 5: Red spectrum
• Group 6: No continuum

Table 6 contains the classifications:

Table in ASCII format (109k), column definitions and notes.

For a more complete explanation of each classification group and subgroup, see the catalogs page.

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Last modified 28 May, 2008. © Gregory C. Sloan and others.