Volume 658, February 2022
|Number of page(s)||12|
|Published online||26 January 2022|
Time evolution of magnetic activity cycles in young suns: The curious case of κ Ceti
Department of Astrophysics, University of Vienna,
2 European Space Agency, European Space Research and Technology Centre, Keplerlaan 1, 2201-AZ Noordwijk, The Netherlands
3 Department of Physics and Space Science, Royal Military College of Canada, PO Box 17000, Station Forces, Kingston, ON K7K 0C6, Canada
4 Tartu Observatory, University of Tartu, Observatooriumi 1, Tõravere, 61602 Tartumaa, Estonia
5 Institute of Astronomy and NAO, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
6 Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
7 Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
8 CNRS, Institut de Recherche en Astrophysique et Planetologie, 14 avenue Edouard Belin, 31400 Toulouse, France
9 Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA
10 Max Planck Institut für Sonnensystemforschung, Justus von Liebig Weg 3, 37077 Göttingen, Germany
11 Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
12 University of Southern Queensland, Centre for Astrophysics, Toowoomba, QLD 4350, Australia
13 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
14 LUPM-UMR 5299, CNRS & Université Montpellier, place Eugène Bataillon, 34095 Montpellier Cedex 05, France
15 Department of Physics, Ariel University, Ariel 40700, Israel
16 School of Physics, Trinity College Dublin, University of Dublin, Dublin-2, Ireland
17 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
Accepted: 18 September 2021
Context. A detailed investigation of the magnetic properties of young Sun-like stars can provide valuable information on our Sun’s magnetic past and its impact on the early Earth.
Aims. We determine the properties of the moderately rotating young Sun-like star κ Ceti’s magnetic and activity cycles using 50 yr of chromospheric activity data and six epochs of spectropolarimetric observations.
Methods. The chromospheric activity was determined by measuring the flux in the Ca II H and K lines. A generalised Lomb–Scargle periodogram and a wavelet decomposition were used on the chromospheric activity data to establish the associated periodicities. The vector magnetic field of the star was reconstructed using the technique of Zeeman Doppler imaging on the spectropolarimetric observations.
Results. Our period analysis algorithms detect a 3.1 yr chromospheric cycle in addition to the star’s well-known ~6 yr cycle period. Although the two cycle periods have an approximate 1:2 ratio, they exhibit an unusual temporal evolution. Additionally, the spectropolarimetric data analysis shows polarity reversals of the star’s large-scale magnetic field, suggesting a ~10 yr magnetic or Hale cycle.
Conclusions. The unusual evolution of the star’s chromospheric cycles and their lack of a direct correlation with the magnetic cycle establishes κ Ceti as a curious young Sun. Such complex evolution of magnetic activity could be synonymous with moderately active young Suns, which is an evolutionary path that our own Sun could have taken.
Key words: stars: magnetic field / stars: imaging / stars: chromospheres / stars: activity / stars: solar-type
© ESO 2022
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.