The relation between stellar magnetic field geometry and chromospheric activity cycles – I. The highly variable field of ε Eridani at activity minimum
Article
Article Title | The relation between stellar magnetic field geometry and chromospheric activity cycles – I. The highly variable field of ε Eridani at activity minimum |
---|---|
ERA Journal ID | 41989 |
Article Category | Article |
Authors | Jeffers, S. V. (Author), Boro Saikia, S. (Author), Barnes, J. R. (Author), Petit, P. (Author), Marsden, S. C. (Author), Jardine, M. M. (Author) and Vidotto, A. A. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society: Letters |
Journal Citation | 471 (1), pp. L96-L100 |
Number of Pages | 5 |
Year | 2017 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 1745-3925 |
1745-3933 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnrasl/slx097 |
Web Address (URL) | https://academic.oup.com/mnrasl/article-abstract/471/1/L96/4044700 |
Abstract | The young and magnetically active K dwarf eps Eridani exhibits a chromospheric activity cycle of about 3 yr. Previous reconstructions of its large-scale magnetic field show strong variations at yearly epochs. To understand how eps Eridani’s large-scale magnetic field geometry evolves over its activity cycle, we focus on high-cadence observations spanning 5 months at its activity minimum. Over this time-span, we reconstruct three maps of eps Eridani’s large-scale magnetic field using the tomographic technique of Zeeman–Doppler imaging. The results show that at the minimum of its cycle, eps Eridani’s large-scale field is more complex than the simple dipolar structure of the Sun and 61 Cyg A at minimum. Additionally, we observe a surprisingly rapid regeneration of a strong axisymmetric toroidal field as eps Eridani emerges from its S-index activity minimum. Our results show that all stars do not exhibit the same field geometry as the Sun, and this will be an important constraint for the dynamo models of active solar-type stars. |
Keywords | polarimetric, stars, eps Eridani, magnetic field, solar-type |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters ©: 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Georg August University of Gottingen, Germany |
Open University, United Kingdom | |
French National Centre for Scientific Research, France | |
Computational Engineering and Science Research Centre | |
University of St Andrews, United Kingdom | |
University of Dublin, Ireland | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q4888/the-relation-between-stellar-magnetic-field-geometry-and-chromospheric-activity-cycles-i-the-highly-variable-field-of-eridani-at-activity-minimum
Download files
771
total views62
total downloads2
views this month1
downloads this month