SIMBAD references

1998A&AS..133..201I - Astron. Astrophys., Suppl. Ser., 133, 201-209 (1998/December-1)

Spectral classification of unidentified IRAS sources with Fν(12µm)≥Fν(25µm).


Abstract (from CDS):

Spectral types of a large number of unidentified IRAS Point Sources with Fν(12µm)≥Fν(25µm) were determined; the majority are faint, oxygen-rich (M-type) or carbon-rich giant stars. The Guide Star Catalog has been used to find the photographic magnitudes of the newly classified IRAS sources with quality-3 flux densities at 12µm in order to determine their Bj-[12] colour index. The dependence of this and of the IRAS indices on spectral type is determined and discussed. The mean [12]-[25] colour of the M-type stars is found to increase monotonically from M3 to M6 and then levels off. Comparison of the [12]-[25] colours of these faint IRAS M stars with those of Bright Star Catalog M stars indicates that, at all types, the mean [12]-[25] index of the former group is higher than that of the latter by at least 0.2 magnitude, and this is found to be significant at the 95% confidence level. Comparison of the quality-3, mean [25]-[60] colours of the newly-classified, faint M stars with those of BSC stars over the same spectral type also shows the same trend. Possible reasons for this difference are discussed. The percentage of variable sources as a function of spectral type is seen to sharply increase from a nearly constant value of about 25% for sources of spectral type M3 to M7 to a value of about 50% at M10. The mean [12]-[25] colours of the IRAS unidentified sources (within the limits of the errors on their mean values) appear to be rather insensitive to the degree of variability.

Abstract Copyright:

Journal keyword(s): stars: AGB - stars: carbon - stars: late-type - stars: mass-loss - infrared: stars

VizieR on-line data: <Available at CDS (J/A+AS/133/201): table6.dat table6.tex>

Simbad objects: 157

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:1998A&AS..133..201I and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact