A spectro-polarimetric study of the planet-hosting G dwarf, HD 147513

TL;DR

This spectro-polarimetric study of HD 147513 reveals its magnetic field characteristics, rotation period, and activity level, providing insights into its stellar magnetic topology and activity, with implications for understanding planet-hosting Sun-like stars.

Contribution

First detailed magnetic field mapping of HD 147513 using spectro-polarimetry, linking magnetic activity with stellar rotation and chemical peculiarities.

Findings

Detected Zeeman signatures indicating a magnetic field of 1.0-3.2 G

Estimated stellar rotation period of 10 +/- 2 days

Star exhibits a simple poloidal large-scale magnetic field

Abstract

The results from a spectro-polarimetric study of the planet-hosting Sun-like star, HD 147513 (G5V), are presented here. Robust detections of Zeeman signatures at all observed epochs indicate a surface magnetic field, with longitudinal magnetic field strengths varying between 1.0-3.2 G. Radial velocity variations from night to night modulate on a similar timescale to the longitudinal magnetic field measurements. These variations are therefore likely due to the rotational modulation of stellar active regions rather than the much longer timescale of the planetary orbit (Porb=528 d). Both the longitudinal magnetic field measurements and radial velocity variations are consistent with a rotation period of 10 +/- 2 days, which are also consistent with the measured chromospheric activity level of the star (log R'(HK)=-4.64). Together, these quantities indicate a low inclination angle, i~18 degrees. We present preliminary magnetic field maps of the star based on the above period and find a simple poloidal large-scale field. Chemical analyses of the star have revealed that it is likely to have undergone a barium-enrichment phase in its evolution because of a higher mass companion. Despite this, our study reveals that the star has a fairly typical activity level for its rotation period and spectral type. Future studies will enable us to explore the long-term evolution of the field, as well as to measure the stellar rotation period, with greater accuracy.