planet-star interactions; planetary systems; planets and satellites: dynamical evolution and stability; stars: activity; stars: evolution; stars: rotation; Engulfment; Host-stars; Planet-star interactions; Planetary system; Planets and satellites: dynamical evolution and stabilities; Spin-up; Star: activity; Star: evolution; Stars: Rotation; X-ray luminosity; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Context. The discovery of an increasing variety of exoplanets in very close orbits around their host stars raised many questions about how stars and planets interact and to what extent host stars’ properties may be influenced by the presence of close-by companions. Understanding how the evolution of stars is impacted by the interactions with their planets is indeed fundamental to disentangling their intrinsic evolution from star-planet-interaction (SPI) induced phenomena. In this context, GJ 504 is a promising candidate for a star that underwent strong SPI. Its unusually short rotational period (Prot ∼ 3.4 days), while being in contrast with what is expected of single-star models, could result from the inward migration of a close-by, massive companion (Mpl ≥ 2 MJ), pushed towards its host by the action of tides. Moreover, its brighter emission in the X-ray luminosity may hint at a rejuvenation of the dynamo process sustaining the stellar magnetic field, which is a consequence of the SPI-induced spin-up. Aims. We aim to study the evolution of GJ 504 and establish whether by invoking the engulfment of a planetary companion we can better reproduce its rotational period and X-ray luminosity. Methods. We simulated the past evolution of the star by assuming two different scenarios: ‘star without close-by planet’ and ‘star with close-by planet’. In the second scenario, we use our SPI code to investigate how the inward migration and eventual engulfment of a giant planet driven by stellar tides may spin-up the stellar surface and rejuvenate its dynamo. We compare our theoretical tracks with archival-rotational-period and X-ray data of GJ 504 collected from the all-sky surveys of the ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Russian Spektrum-Roentgen-Gamma mission (SRG). Results. Despite the large uncertainty on the stellar age, we find that the second evolutionary scenario characterised by the inward migration of a massive planetary companion is in better agreement with the short rotational period and the bright X-ray luminosity of GJ 504; thus, it strongly favours the inward migration scenario over the one in which close-by planets have no tidal impact on the star.
Research Center/Unit :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Pezzotti, Camilla ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR) ; Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Roma, Monteporzio Catone, Italy
Buldgen, Gaël ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Magaudda, E. ; Institut für Astronomie und Astrophysik, Eberhard-Karls Universität Tübingen, Tübingen, Germany
Farnir, Martin ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Van Grootel, Valérie ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Bellotti, S. ; Leiden Observatory, Leiden University, Leiden, Netherlands ; Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, IRAP, UMR 5277, Toulouse, France
Poppenhaeger, K. ; Leibniz Institute for Astrophysics Potsdam (AIP), Potsdam, Germany ; Institute for Physics and Astronomy, University of Potsdam, Potsdam-Golm, Germany
Language :
English
Title :
Planetary inward migration as the potential cause of GJ 504’s fast rotation and bright X-ray luminosity New constraints from eROSITA
We thank the reviewer Dr. Yaroslav Lazovik for his thorough and helpful comments, that helped to improve the quality and clarity of the manuscript. CP thanks the Belgian Federal Science Policy Office (BEL-SPO) for the financial support in the framework of the PRODEX Program of the European Space Agency (ESA) under contract number 4000141194. GB is funded by the Fonds National de la Recherche Scientifique (FNRS). EM is supported by Deutsche Forschungsgemeinschaft under grant STE 1068/8-1. This work is based on data from eROSITA, the soft X-ray instrument aboard SRG, a joint Russian-German science mission supported by the Russian Space Agency (Roskosmos), in the interests of the Russian Academy of Sciences represented by its Space Research Institute (IKI), and the Deutsches Zentrum f\u00FCr Luft- und Raumfahrt (DLR). The SRG spacecraft was built by Lavochkin Association (NPOL) and its subcontractors, and is operated by NPOL with support from the Max Planck Institute for Extraterrestrial Physics (MPE). The development and construction of the eROSITA X-ray instrument was led by MPE, with contributions from the Dr. Karl Remeis Observatory Bamberg & ECAP (FAU Erlangen-Nuernberg), the University of Hamburg Observatory, the Leibniz Institute for Astrophysics Potsdam (AIP), and the Institute for Astronomy and Astrophysics of the University of T\u00FCbingen, with the support of DLR and the Max Planck Society. The Argelander Institute for Astronomy of the University of Bonn and the Ludwig Maximilians Universit\u00E4t Munich also participated in the science preparation for eROSITA. The eROSITA data shown here were processed using the eSASS/NRTA software system developed by the German eROSITA consortium. VVG is an F.R.S.-FNRS Research Associate. SB acknowledges funding from the Dutch Research Council (NWO) with project number OCENW.M.22.215 of the research program \u2018Open Competition Domain Science- M\u2019.We thank the reviewer Dr. Yaroslav Lazovik for his thorough and helpful comments, that helped to improve the quality and clarity of the manuscript. CP thanks the Belgian Federal Science Policy Office (BELSPO) for the financial support in the framework of the PRODEX Program of the European Space Agency (ESA) under contract number 4000141194. GB is funded by the Fonds National de la Recherche Scientifique (FNRS). EM is supported by Deutsche Forschungsgemeinschaft under grant STE 1068/8-1. This work is based on data from eROSITA, the soft X-ray instrument aboard SRG, a joint Russian-German science mission supported by the Russian Space Agency (Roskosmos), in the interests of the Russian Academy of Sciences represented by its Space Research Institute (IKI), and the Deutsches Zentrum f\u00FCr Luft- und Raumfahrt (DLR). The SRG spacecraft was built by Lavochkin Association (NPOL) and its subcontractors, and is operated by NPOL with support from the Max Planck Institute for Extraterrestrial Physics (MPE). The development and construction of the eROSITA X-ray instrument was led by MPE, with contributions from the Dr. Karl Remeis Observatory Bamberg & ECAP (FAU Erlangen-Nuernberg), the University of Hamburg Observatory, the Leibniz Institute for Astrophysics Potsdam (AIP), and the Institute for Astronomy and Astrophysics of the University of T\u00FCbingen, with the support of DLR and the Max Planck Society. The Argelander Institute for Astronomy of the University of Bonn and the Ludwig Maximilians Universit\u00E4t Munich also participated in the science preparation for eROSITA. The eROSITA data shown here were processed using the eSASS/NRTA software system developed by the German eROSITA consortium. VVG is an F.R.S.-FNRS Research Associate. SB acknowledges funding from the Dutch Research Council (NWO) with project number OCENW.M.22.215 of the research program \u2018Open Competition Domain Science- M\u2019.
