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  Far beyond the Sun – I. The beating magnetic heart in Horologium

Alvarado-Gómez, J. D., Hussain, G. A. J., Drake, J. J., Donati, J.-F., Sanz-Forcada, J., Stelzer, B., et al. (2018). Far beyond the Sun – I. The beating magnetic heart in Horologium. Monthly Notices of the Royal Astronomical Society, 473(4), 4326-4338. doi:10.1093/mnras/stx2642.

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Item Permalink: http://hdl.handle.net/21.11116/0000-0003-3258-2 Version Permalink: http://hdl.handle.net/21.11116/0000-0003-3259-1
Genre: Journal Article


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Alvarado-Gómez, Julián D., Author
Hussain, Gaitee A. J., Author
Drake, Jeremy J., Author
Donati, Jean-François, Author
Sanz-Forcada, Jorge, Author
Stelzer, Beate, Author
Cohen, Ofer, Author
Amazo-Gómez, Eliana M.1, 2, Author
Grunhut, Jason H., Author
Garraffo, Cecilia, Author
Moschou, Sofia P., Author
Silvester, James, Author
Oksala, Mary E., Author
1International Max Planck Research School for Solar System Science at the University of Göttingen, Max Planck Institute for Solar System Research, Max Planck Society, Justus-von-Liebig-Weg 3, 37077 Göttingen, DE, ou_1832290              
2Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society, Justus-von-Liebig-Weg 3, 37077 Göttingen, DE, ou_1832289              


Free keywords: techniques: polarimetric, stars: activity, stars: individual: ι Hor, stars: individual: HD 17051, stars: individual: HR 810, stars: magnetic field, stars: solar-type
 Abstract: A former member of the Hyades cluster, ι Horologii (ι Hor) is a planet-hosting Sun-like star which displays the shortest coronal activity cycle known to date (Pcyc ∼ 1.6 yr). With an age of ∼625 Myr, ι Hor is also the youngest star with a detected activity cycle. The study of its magnetic properties holds the potential to provide fundamental information to understand the origin of cyclic activity and stellar magnetism in late-type stars. In this series of papers, we present the results of a comprehensive project aimed at studying the evolving magnetic field in this star and how this evolution influences its circumstellar environment. This paper summarizes the first stage of this investigation, with results from a long-term observing campaign of ι Hor using ground-based high-resolution spectropolarimetry. The analysis includes precise measurements of the magnetic activity and radial velocity of the star, and their multiple time-scales of variability. In combination with values reported in the literature, we show that the long-term chromospheric activity evolution of ι Hor follows a beating pattern, caused by the superposition of two periodic signals of similar amplitude at P1 ≃ 1.97 ± 0.02 yr and P2 ≃ 1.41 ± 0.01 yr. Additionally, using the most recent parameters for ι Hor b in combination with our activity and radial velocity measurements, we find that stellar activity dominates the radial velocity residuals, making the detection of additional planets in this system challenging. Finally, we report here the first measurements of the surface longitudinal magnetic field strength of ι Hor, which displays varying amplitudes within ±4 G and served to estimate the rotation period of the star ( Prot=7.70(+0.18)(−0.67) d).


Language(s): eng - English
 Dates: 2019-03-192018
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Method: Peer
 Identifiers: DOI: 10.1093/mnras/stx2642
 Degree: -



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Title: Monthly Notices of the Royal Astronomical Society
  Other : Mon. Not. R. Astron. Soc.
Source Genre: Journal
Publ. Info: Oxford : Oxford University Press
Pages: - Volume / Issue: 473 (4) Sequence Number: - Start / End Page: 4326 - 4338 Identifier: ISSN: 1365-8711
CoNE: https://pure.mpg.de/cone/journals/resource/1000000000024150