Skip to main content

OGLE-BLG-RRLYR-12245: An RR Lyrae Star that Switched from a Double to Single-mode Pulsation

We recently released a significant update to the backend systems for the AAVSO website. While most of the bugs introduced by this update have been fixed, there may still be problems we haven't fixed. If you run into a problem, please email

We report the discovery of an RR Lyrae star that experienced a switching of its pulsation mode. OGLE-BLG-RRLYR-12245 was discovered as a double-mode RRd star from the observations conducted in years 2001-2006 during the third phase of the Optical Gravitational Lensing Experiment (OGLE-III). The OGLE-IV observations carried out since 2010 reveal that this object is now a fundamental-mode RRab star, with no sign of the first-overtone pulsation. The analysis of the OGLE photometry shows that the final stage of the mode switching occurred on a relatively short timescale of a few months in 2005. We study the behavior of the star during this process, showing changes of the pulsational amplitudes and periods. We also discuss possible causes for the mode switching in RR Lyr stars.

Authors:  I. Soszynski, W. A. Dziembowski, A. Udalski, M. K. Szymanski, M. Kubiak, G. Pietrzynski, L. Wyrzykowski, K. Ulaczyk, R. Poleski, S. Kozlowski, P. Pietrukowicz, J. Skowron, P. Mroz

Read the paper on arXiv

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484