Periodicity in the Light Curve of P Cygni - Indication for a Binary Companion?

TL;DR

This study analyzes seven decades of observations of P Cygni, revealing a 4.7-year periodicity in its luminosity that suggests the star may have a binary companion, potentially impacting models of LBV eruptions.

Contribution

It provides the first observational evidence of a possible binary companion to P Cygni based on long-term light curve analysis.

Findings

Identified a 4.7-year periodicity in P Cygni's light curve.

Suggests the periodicity may be due to a binary companion causing eclipse-like events.

Supports models linking LBV eruptions to binary interactions.

Abstract

We use observations of the Luminous Blue Variable (LBV) P Cygni spanning seven decades, along with signal processing methods, to identify a periodicity in the stellar luminosity. We find a distinct period of $4.7 \pm 0.3$ years together with shorter periods. The periodicity is a possible indication of a binary companion passing in an eclipse-like event from the dense LBV wind, and if so it is the first observational indication that P Cygni is a binary system. This may support models that contribute giant LBV eruptions to interaction with a binary companion. We discuss other interpretations for the periodicity as well.