Miras and Semiregular Variables in the Large Magellanic Cloud

We use the OGLE-II and OGLE-III data in conjunction with the 2MASS near-infrared (NIR) photometry to identify and study Miras and Semiregular Variables (SRV) in the Large Magellanic Cloud. We found in total 3221 variables of both types, populating two of the series of NIR period-luminosity (PL) sequences. The majority of these objects are double periodic pulsators, with periods belonging to both PL ridges. We indicate that in the period - Wesenheit index plane the oxygen-rich and carbon-rich AGB stars from the NIR PL sequences C, C' and D split into well separated ridges. Thus, we discover an effective method of distinguishing between O-rich and C-rich Miras, SRV and stars with Long Secondary Periods using their V and I band photometry. We present an empirical method of estimating the mean Ks magnitudes of the Long Period Variables using single-epoch Ks measurements and complete light curves in the I band. We utilize these corrected magnitudes to show that the O-rich and C-rich Miras and SRV follow somewhat different Ks band PL relations.

Full resolution paper is available from the OGLE Internet archive.

Click to see larger map

PLEASE cite the following paper when using the data or referring to these OGLE results:
SoszyŮski et al., 2005, Acta Astron., 55, 331.