Eridani: an active K dwarf and a planet hosting star? The variability of its large-scale magnetic field topology

Jeffers, S. V. and Petit, P. and Marsden, S. C. and Morin, J. and Donati, J. -F. and Folsom, C. P. (2014) Eridani: an active K dwarf and a planet hosting star? The variability of its large-scale magnetic field topology. Astronomy and Astrophysics, 569. pp. 1-8. ISSN 0004-6361

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Abstract

The young K-dwarf Eridani is an example of a young active planet hosting star that has shown over long-term monitoring of its chromospheric emission to exhibit cyclic magnetic activity. In this paper, we investigate how Eridani's large-scale magnetic field geometry evolves over the timescale of its S-index cycle using spectropolarimetric observations and the technique of Zeeman-Doppler imaging. Our observations comprise six epochs secured over a time period of nearly seven years, with each almost yearly observational epoch showing a dramatic change in the large-scale magnetic field topology, with no stable regions. The poloidal field varies from strongly dipolar to mono-polar and the toroidal field is non-existent to begin with and then emerges to dominate the magnetic field energy before disappearing and re-emerging again. A potential cycle is detected in the poloidal field, but further observations are needed to confirm this.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © The European Southern Observatory (ESO) 2014. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - No Department
Date Deposited: 19 Jan 2015 22:56
Last Modified: 07 Jul 2016 06:09
Uncontrolled Keywords: magnetic fields; star activity; starspots
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020108 Planetary Science (excl. Extraterrestrial Geology)
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020107 Mesospheric, Ionospheric and Magnetospheric Physics
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1051/0004-6361/201423725
URI: http://eprints.usq.edu.au/id/eprint/26585

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