Periods in a 87 Years Light Curve of the Symbiotic Star MWC 560

TL;DR

This study presents an 87-year visual light curve of the symbiotic star MWC 560, identifying three fundamental periodic components linked to physical mechanisms such as magnetic dynamo activity, binary orbit, and stellar rotation.

Contribution

It provides a comprehensive long-term light curve analysis and attributes observed periodicities to specific physical processes in the system, enhancing understanding of symbiotic star variability.

Findings

Three main periodicities identified: 19000 d, 1943 d, 722 d.

Periodicities attributed to magnetic dynamo, orbital, and rotational cycles.

Similar characteristics found in other symbiotic stars.

Abstract

We have constructed a visual light curve of the symbiotic star MWC covering the last 87 years of its history. The data were assembled from the literature and from the AAVSO data bank. Most of the periodic components of the system brightness variation can be accounted for by the operation of 3 basic clocks of the periods P1=19000 d, P2=1943 d and P3=722 d. These periods can plausibly, and consistently with the observations, be attributed to 3 physical mechanisms in the system. They are, respectively, the working of a solar-like magnetic dynamo cycle in the outer layers of the giant star of the system, the binary orbit cycle and the sidereal rotation cycle of the giant star. MWC 560 is the 7th symbiotic star with historical light curves that reveal similar basic characteristics of the systems. The light curves of all these stars are well interpreted on the basis of current understanding of the physical processes that are the major sources of the optical luminosity of these symbiotic systems.