dc.contributor.author |
Iyengar, K. V. K |
|
dc.contributor.author |
MacConnell, D. J |
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dc.date.accessioned |
2008-08-22T11:16:31Z |
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dc.date.available |
2008-08-22T11:16:31Z |
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dc.date.issued |
1998-12 |
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dc.identifier.citation |
Astronomy and Astrophysics Supplement, Vol. 133, No. 2, pp. 201 - 209 |
en |
dc.identifier.issn |
0365 - 0138 |
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dc.identifier.uri |
http://hdl.handle.net/2248/3263 |
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dc.description.abstract |
Spectral types of a large number of unidentified IRAS Point Sources with F{_nu }(12 μm) >= F{_nu }(25 μm) 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 12 μm in order to determine their {B_j -[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. Table 6 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130 79 128 5) or via http://cdsweb.u-strasbg.fr/Abstract.html |
en |
dc.format.extent |
368131 bytes |
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dc.format.mimetype |
application/pdf |
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dc.language.iso |
en |
en |
dc.publisher |
The European Southern Observatory |
en |
dc.relation.uri |
http://dx.doi.org/10.1051/aas:1998316 |
en |
dc.subject |
Stars: AGB |
en |
dc.subject |
Stars: Carbon |
en |
dc.subject |
Stars: Late-type |
en |
dc.subject |
Stars: Mass-loss |
en |
dc.subject |
Infrared: Stars |
en |
dc.title |
Spectral classification of unidentified IRAS sources with F{_nu }(12 μm) >= F{_nu }(25 μm) |
en |
dc.type |
Article |
en |