A BCool magnetic snapshot survey of solar-type stars
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We present the results of a major high-resolution spectropolarimetric BCool project magnetic survey of 170 solar-type stars. Surface magnetic fields were detected on 67 stars, with 21 classified as mature solar-type stars, a result that increases by a factor of 4 the number of mature solar-type stars on which magnetic fields have been observed. In addition, a magnetic field was detected for 3 out of 18 of the subgiant stars surveyed. For the population of K-dwarfs, the mean value of |Bl| (|Bl|mean) was also found to be higher (5.7 G) than |Bl|mean measured for the G-dwarfs (3.2 G) and the F-dwarfs (3.3 G). For the sample as a whole, |Bl|mean increases with rotation rate and decreases with age, and the upper envelope for |Bl| correlates well with the observed chromospheric emission. Stars with a chromospheric S-index greater than about 0.2 show a high magnetic field detection rate and so offer optimal targets for future studies. This survey constitutes the most extensive spectropolarimetric survey of cool stars undertaken to date, and suggests that it is feasible to pursue magnetic mapping of a wide range of moderately active solar-type stars to improve our understanding of their surface fields and dynamos.
Marsden , S C , Petit , P , Jeffers , S V , Morin , J , Fares , R , Reiners , A , do Nascimento , J -D , Auriere , M , Bouvier , J , Carter , B D , Catala , C , Dintrans , B , Donati , J -F , Gastine , T , Jardine , M , Konstantinova-Antova , R , Lanoux , J , Lignieres , F , Morgenthaler , A , Ramirez-Velez , J C , Theado , S , Van Grootel , V & BCool Collaboration 2014 , ' A BCool magnetic snapshot survey of solar-type stars ' Monthly Notices of the Royal Astronomical Society , vol 444 , no. 4 , pp. 3517-3536 . DOI: 10.1093/mnras/stu1663
Monthly Notices of the Royal Astronomical Society
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
SVJ acknowledges research funding by the Deutsche Forschungsgemeinschaft (DFG) under grant SFB 963/1, project A16. JM was funded by a fellowship of the Alexander von Humboldt Foundation in Göttingen. RF acknowledges funding from the STFC.
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