Magnetic fields and differential rotation on the pre-main sequence -I. The early-G star HD 141943 - brightness and magnetic topologies
Article
Article Title | Magnetic fields and differential rotation on the pre-main sequence -I. The early-G star HD 141943 - brightness and magnetic topologies |
---|---|
ERA Journal ID | 1074 |
Article Category | Article |
Authors | Marsden, S. C. (Author), Jardine, M. M. (Author), Ramirez Velez, J. C. (Author), Alecian, E. (Author), Brown, C. J. (Author), Carter, B. D. (Author), Donati, J.-F. (Author), Dunstone, N. (Author), Hart, R. (Author), Semel, M. (Author) and Waite, I. A. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 413 (3), pp. 1922-1938 |
Number of Pages | 17 |
Year | 2011 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1111/j.1365-2966.2011.18367.x |
Web Address (URL) | https://academic.oup.com/mnras/article/413/3/1922/966220 |
Abstract | Spectroscopic and spectropolarimetric observations of the pre-main sequence early-G star HD 141943 were obtained at four observing epochs (in 2006, 2007, 2009 and 2010). The observations were undertaken at the 3.9-m Anglo-Australian Telescope using the UCLES echelle spectrograph and the SEMPOL spectropolarimeter visitor instrument. Brightness and surface magnetic field topologies were reconstructed for the star using the technique of least-squares deconvolution to increase the signal-to-noise ratio of the data. The reconstructed brightness maps show that HD 141943 had a weak polar spot and a significant amount of low-latitude features, with little change in the latitude distribution of the spots over the 4 yr of observations. The surface magnetic field was reconstructed at three of the epochs from a high-order (l≤ 30) spherical harmonic expansion of the spectropolarimetric observations. The reconstructed magnetic topologies show that in 2007 and 2010 the surface magnetic field was reasonably balanced between poloidal and toroidal components. However, we find tentative evidence of a change in the poloidal/toroidal ratio in 2009 with the poloidal component becoming more dominant. At all epochs the radial magnetic field is predominantly non-axisymmetric while the azimuthal field is predominantly axisymmetric with a ring of positive azimuthal field around the pole similar to that seen on other active stars. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS. |
Keywords | Line: profiles; Magnetic fields; Stars: activity; Stars: imaging; Stars: individual: HD 141943; Starspots |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
510203. Nonlinear optics and spectroscopy | |
490412. Topology | |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2011 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | James Cook University |
University of St Andrews, United Kingdom | |
Paris Sciences and Letters University, France | |
Laboratory of Space Science and Astrophysical Instrumentation, France | |
Department of Biological and Physical Sciences | |
Institute for Research in Astrophysics and Planetology, France | |
Office of Research | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q1184/magnetic-fields-and-differential-rotation-on-the-pre-main-sequence-i-the-early-g-star-hd-141943-brightness-and-magnetic-topologies
Download files
1858
total views125
total downloads2
views this month0
downloads this month