Multisite observations of surface structures on AB Doradus in 1994 November

Andrew Collier Cameron, FM Walter, O Vilhu, T Böhm, C Catala, S Char, FJ Clarke, P Felenbok, BH Foing, KK Ghosh, J Hao, L Huang, DA Jackson, E Janot-Pacheco, S Jiang, A-M Lagrange, N Suntzeff, DS Zhai

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18 Citations (Scopus)


We present time-resolved optical spectroscopy and broad-band photometry of the rapidly rotating southern K0 dwarf star AB Doradus, obtained during 1994 November. The data were obtained as part of a collaboration dedicated to MUlti-SIte COntinuous Spectroscopy (MUSICOS), and entailed coordinated observations on three continents to obtain the fullest phase coverage possible subject to Limitations of local weather conditions. The Doppler images from the three consecutive nights of the run show excellent mutual agreement, with a dark polar cap and numerous intermediate- and low-latitude features. Simultaneous optical photometry showed numerous short-duration U-band flares, and two longer duration optical flares with durations of the order of hours. The latter produced broad-band continuum enhancements throughout the optical spectrum. Where simultaneous spectroscopy was available, both types of flare were seen to have counterparts in H alpha and the Ca II H line. Simultaneous time-resolved ultraviolet spectroscopy from the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope, reported elsewhere, shows that at least one of the short-duration U-band flares was also observed in Cry with the GHRS, Time-series H alpha spectra showed significant evolution of the circumstellar prominence system over five consecutive stellar rotations, One prominence underwent a dramatic increase in distance from the stellar rotation axis. We speculate that this event may have been associated with one of the long-duration flares.

Original languageEnglish
Pages (from-to)493-509
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - 11 Sept 1999


  • stars : activity
  • stars : individual : AB Dor
  • stars : low-mass, brown dwarfs
  • stars : magnetic fields
  • HR-1099


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