Some Notes on IR Color, M12-M25, of Double Stars

The Infrared (IR) color m12-m25 of 923 bright stars is examined. 246 out of 923 are known double stars. The IR-color is defined as -2.5 log (f12/f25) + 1.56; f12 and f25 are IR flux of IRAS Point Sources at 12 and 25 micron in Jansky. It is noticed that the IR-color of some late spectral type (spectral class of G K and M that is 84% out of 923) wide binaries apparently similar (or little bluer) compared to the single star of the same MK spectral type. The range of IR-color of late spectraltype between 0.0 < m12-m25 < 1.2. It is unclear the different of IR-color between single and wide binaries of early spectral type (spectral class of F A and B that is 13% out of 923). The range of IR- color of the early spectral type is between 0.00 < m12-m25 < 3.0. The IR-color indicates the existance of circumstellar dust as well as the resultant of gravitational force and radiation pressure of the system.