THE INFRARED PROPERTIES OF MIRA-TYPE VARIABLES AND OTHER COOL STARS AS DETERMINED FROM JHKL PHOTOMETRY

Extensive infrared photometry of Me(Mira) variables and of C, S, SC and related stars is used to establish two-colour diagrams and periodcolour relations. The characteristic areas in these plots occupied by the different classes of objects are delineated. The main aim is to provide a norm with which other stars (e.g. red variables in the Galactic Centre and in the Magellanic Clouds and peculiar stars) can be compared. The {J-H) versus period relation offers a method for determining the interstellar reddenings of Me variables. The strong concentration to the longer periods of Miras which are OH masers is probably due primarily to the fact that in the sample surveyed, these stars also have the brightest apparent bolometric magnitudes. Period-amplitude plots are shown for Me variables. The Mira components in symbiotic stars are found to have exceptionally large amplitudes. © Royal Astronomical Society.