Doppler images and chromospheric variability of TWA 6

M. B. Skelly, Y. C. Unruh, A. Collier Cameron, J. R. Barnes, J. -F. Donati, W. A. Lawson, B. D. Carter

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37 Citations (Scopus)

Abstract

We present Doppler imaging and Balmer line analysis of the weak-line T Tauri star TWA 6. Using these data we have made one of the first attempts to measure differential rotation in a T Tauri star, and the first detection of a slingshot prominence in such a star. We also show the most direct evidence to date of the existence of solar-type plages in a star other than the Sun.

Observations were made over six nights: 2006 February 11-13 and 2006 February 18-20, when spectra were taken with the UCL Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope. Using least-squares deconvolution to improve the effective signal-to-noise ratio we produced two Doppler maps. These show similar features to maps of other rapidly rotating T Tauri stars, i.e. a polar spot with more spots extending out of it down to equator. Comparison of the two maps was carried out to measure the differential rotation. Cross-correlation and parameter fitting indicates that TWA 6 does not have detectable differential rotation.

The Balmer emission of the star was studied. The mean H alpha profile has a narrow component consistent with rotational broadening and a broad component extending out to +/- 250 km s(-1). The variability in H alpha suggests that the chromosphere has active regions that are cospatial with the spots in the photosphere, similar to the 'plages' observed on the Sun. In addition the star has at least one slingshot prominence 3R(*) above the surface - the first such detection in a T Tauri star.

Original languageEnglish
Pages (from-to)708-718
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume385
Issue number2
Early online date21 Feb 2008
DOIs
Publication statusPublished - 1 Apr 2008

Keywords

  • stars : individual : TWA 6
  • stars : late-type
  • stars : magnetic fields
  • stars : pre-main-sequence
  • stars : rotation
  • stars : spots
  • PRE-MAIN-SEQUENCE
  • T-TAURI STARS
  • LOW-MASS STARS
  • DIFFERENTIAL ROTATION
  • YOUNG STARS
  • AB DORADUS
  • HYDRAE ASSOCIATION
  • MAGNETIC-FIELD
  • ACTIVE STARS
  • EVOLUTION

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