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

¹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
e-mail: ghussain@eso.org
² Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, UPS-OMP, 31400 Toulouse, France
³ Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679 München, Germany
⁴ CNRS, Institut de Recherche en Astrophysique et Planétologie, 14 avenue Edouard Belin, 31400 Toulouse, France
⁵ Univ. Grenoble Alpes, IPAG, 38000 Grenoble, France
⁶ CNRS, IPAG, 38000 Grenoble, France
⁷ LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Univ. Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
⁸ LUPM-UMR 5299, CNRS & Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
⁹ INAF–Osservatorio Astrofisico di Catania, via Santa Sofia 78, 95123 Catania, Italy
¹⁰ SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK
¹¹ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹² Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
¹³ Astronomy Department, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459, USA
¹⁴ Department of Physics and Astronomy, Stony Brook University, Stony Brook NY 11794-3800, USA

Received: 25 May 2015
Accepted: 7 September 2015

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 (P_orb = 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°. 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.