On the characterization of GJ 504: a magnetically active planet-host star observed by the Transiting Exoplanet Survey Satellite (TESS)

TL;DR

This study analyzes TESS photometric data of GJ 504, revealing high magnetic activity that suppresses solar-like oscillations, and characterizes its magnetic cycle and evolutionary stage as an active early main sequence star.

Contribution

The paper provides a detailed analysis of GJ 504's magnetic activity, rotational period, and magnetic cycle, clarifying its evolutionary status and the impact of magnetic activity on stellar oscillations.

Findings

No solar-like pulsations detected, likely due to magnetic activity.

Magnetic cycle of approximately 12 years confirmed.

Stellar rotation period measured at 3.4 days.

Abstract

We present the results of the analysis of the photometric data collected in long and short-cadence mode by the Transiting Exoplanet Survey Satellite (TESS) for GJ 504, a well studied planet-hosting solar-like star, whose fundamental parameters have been largely debated during the last decade. Several attempts have been made by the present authors to isolate the oscillatory properties expected on this main-sequence star, but we did not find any presence of solar-like pulsations. The suppression of the amplitude of the acoustic modes can be explained by the high level of magnetic activity revealed for this target, not only by the study of the photometric light-curve, but also by the analysis of three decades available of Mount Wilson spectroscopic data. In particular, our measurements of the stellar rotational period Prot=3.4 d and of the main principal magnetic cycle of 12 a confirm previous findings and allow us to locate this star in the early main sequence phase of its evolution during which the chromospheric activity is dominated by the superposition of several cycles before the transition to the phase of the magnetic-braking shutdown with the subsequent decrease of the magnetic activity.