Magnetic topologies of two weak-line T Tauri stars TAP 4 and TAP 40
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We present a Zeeman-Doppler imaging study of two weak-line T Tauri stars TAP 4 and TAP 40, based on the high-resolution spectropolarimetric observations with ESPaDOnS at the Canada-France-Hawaii Telescope in November 2013, in the framework of the MaTYSSE large programme. We apply two Zeeman-Doppler imaging codes to the Stokes I and V profiles to reconstruct their brightness and large-scale magnetic field images. The results given by the two imaging codes are in good agreement with each other. TAP 4 shows a large polar cool spot and several intermediate-latitude warm spots on its surface, whereas TAP 40 exhibits very weak variations in its Stokes I profiles suggesting a mostly unspotted photosphere. We detect Zeeman signatures in the Stokes V profiles of both stars. The reconstructed magnetic maps reveal dominantly toroidal fields, which enclose about 60 per cent of the total magnetic energy for both of TAP 4 and TAP 40. Both stars show prominent circular ring features of the azimuthal magnetic field. We derive a solar-like surface differential rotation on TAP 4 from the tomographic modelling. The brightness image of TAP 4 is used to predict the radial velocity jitters induced by its activity. After filtering out the activity jitter, the RMS of its RVs is reduced from 1.7 km s−1 to 0.2 km s−1, but we do not detect any periodic signals in the filtered RVs of TAP 4, implying that it is unlikely to host a close-in exoplanet more massive than ∼3.5 MJup at 0.1 au.
Xiang , Y , Gu , S , Donati , J-F , Hussain , G A J , Cameron , A C & MaTYSSE Collaboration 2023 , ' Magnetic topologies of two weak-line T Tauri stars TAP 4 and TAP 40 ' , Monthly Notices of the Royal Astronomical Society . https://doi.org/10.1093/mnras/stad363
Monthly Notices of the Royal Astronomical Society
Copyright © 2023 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1093/mnras/stad363.
DescriptionThis study is supported by the National Natural Science Foundation of China under grants Nos.10373023, 10773027, U1531121, 11603068 and 11903074. We acknowledge the science research grant from the China Manned Space Project with NO. CMS-CSST-2021-B07. JFD acknowledges funding from the European Research Council (ERC) under the H2020 research & innovation programme (grant agreement #740651 NewWorlds).
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