Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha

Hussain, G. A. J. and Collier Cameron, A. and Jardine, M. M. and Dunstone, N. and Ramirez Velez, J. and Stempels, H. C. and Donati, J.-F. and Semel, M. and Aulanier, G. and Harries, T. and Bouvier, J. and Dougados, C. and Ferreira, J. and Carter, B. D. and Lawson, W. A. (2009) Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha. Monthly Notices of the Royal Astronomical Society, 398 (1). pp. 189-200. ISSN 0035-8711

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Abstract

We have produced brightness and magnetic field maps of the surfaces of CV Cha and CR Cha: two actively accreting G- and K-type T Tauri stars in the Chamaeleon I star-forming cloud with ages of 3–5 Myr. Our magnetic field maps show evidence for strong, complex multipolar fields similar to those obtained for young rapidly rotating main-sequence stars. Brightness maps indicate the presence of dark polar caps and low-latitude spots – these brightness maps are very similar to those obtained for other pre-main-sequence and rapidly rotating main-sequence stars.

Only two other classical T Tauri stars have been studied using similar techniques so far: V2129 Oph and BP Tau. CV Cha and CR Cha show magnetic field patterns that are significantly more complex than those recovered for BP Tau, a fully convective T Tauri star.

We discuss possible reasons for this difference and suggest that the complexity of the stellar magnetic field is related to the convection zone; with more complex fields being found in T Tauri stars with radiative cores (V2129 Oph, CV Cha and CR Cha). However, it is clearly necessary to conduct magnetic field studies of T Tauri star systems, exploring a wide range of stellar parameters in order to establish how they affect magnetic field generation, and thus how these magnetic fields are likely to affect the evolution of T Tauri star systems as they approach the main sequence.

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Item Type:	Article (Commonwealth Reporting Category C)
Refereed:	Yes
Item Status:	Live Archive
Additional Information:	Pre-print template-style version deposited in accordance with the copyright policy of the publisher. The definitive version is available at www.blackwell-synergy.com.
Depositing User:	Dr Brad Carter
Faculty / Department / School:	Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited:	17 Feb 2010 05:59
Last Modified:	11 Oct 2013 01:34
Uncontrolled Keywords:	stars; formation; imaging; individual; CR Cha; CV Cha; magnetic fields; open clusters and associations; Chamaeleon I
Fields of Research :	02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems 04 Earth Sciences > 0401 Atmospheric Sciences > 040108 Tropospheric and Stratospheric Physics 02 Physical Sciences > 0204 Condensed Matter Physics > 020402 Condensed Matter Imaging 09 Engineering > 0909 Geomatic Engineering > 090905 Photogrammetry and Remote Sensing
Socio-Economic Objective:	E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI:	doi: 10.1111/j.1365-2966.2009.14881.x
URI:	http://eprints.usq.edu.au/id/eprint/5765

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