Zeeman-Doppler imaging of five young solar-type stars
Article
Article Title | Zeeman-Doppler imaging of five young solar-type stars |
---|---|
ERA Journal ID | 1050 |
Article Category | Article |
Authors | Willamo, T. (Author), Lehtinen, J. J. (Author), Hackman, T. (Author), Kapyla, M. J. (Author), Kochukhov, O. (Author), Jeffers, S. V. (Author), Korhonen, H. (Author) and Marsden, S. C. (Author) |
Journal Title | Astronomy and Astrophysics: a European journal |
Journal Citation | 659, pp. 1-16 |
Article Number | A71 |
Number of Pages | 16 |
Year | 2022 |
Publisher | EDP Sciences |
Place of Publication | France |
ISSN | 0004-6361 |
1432-0746 | |
Digital Object Identifier (DOI) | https://doi.org/10.1051/0004-6361/202141649 |
Web Address (URL) | https://www.aanda.org/articles/aa/full_html/2016/03/aa27320-15/aa27320-15.html |
Abstract | Context. The magnetic activity of the Sun changes with the solar cycle. Similar cycles are found in other stars as well, but their details are not known to a similar degree. Characterising stellar magnetic cycles is important for the understanding of the stellar and solar dynamos that are driving the magnetic activity. Aims. We present spectropolarimetric observations of five young, solar-type stars and compare them to previous observations, with the aim to identify and characterise stellar equivalents of the solar cycle. Methods. We use Zeeman-Doppler imaging (ZDI) to map the surface magnetic field and brightness of our targets. The magnetic field is decomposed into spherical harmonic expansions, from which we report the strengths of the axisymmetric versus non-axisymmetric and poloidal versus toroidal components, and we compare them to the Rossby numbers of the stars. Results. We present five new ZDI maps of young, solar-type stars from December 2017. Of special interest is the case of V1358 Ori, which had gone through a polarity reversal between our observations and earlier ones. A less evident polarity reversal might also have occurred in HD 35296. There is a preference for a more axisymmetric field, and possibly a more toroidal field, for the more active stars with lower Rossby number, but a larger sample should be studied to draw any strong conclusions from this. For most of the individual stars, the amounts of toroidal and poloidal field have stayed on levels similar to those in earlier observations. Conclusions. We find evidence for a magnetic polarity reversal having occurred in V1358 Ori. An interesting target for future observations is I1 Ori, which may have a short magnetic cycle of a few years. The correlation between the brightness maps and the magnetic field is mostly poor, which could indicate the presence of small-scale magnetic features of different polarities that cancel one another out and are thus not resolved in our maps. |
Keywords | Stars: activity; Stars: magnetic field; Stars: solar-type; Starspots |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Byline Affiliations | University of Helsinki, Finland |
University of Turku, Finland | |
Aalto University, Finland | |
Uppsala University, Sweden | |
Max Planck Society, Germany | |
European Southern Observatory (ESO), Chile | |
Centre for Astrophysics | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q7vxw/zeeman-doppler-imaging-of-five-young-solar-type-stars
Download files
81
total views34
total downloads0
views this month0
downloads this month