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Paper: A possible activity cycle for AB Aurigae
Volume: 9, Cool Stars, Stellar Systems, and the Sun: Sixth Cambridge Workshop
Page: 310
Authors: Simon, T.; Catala, C.; Praderie, F.
Abstract: IUE spectra of the pre-main sequence Ae star AB Aur exhibit periodic changes in the displacement of the violet edge of the Mg II resonance lines on rotational time scales of 35-45 hours. This modulation in velocity may be induced by a stellar magnetic field, which organizes the wind of AB Aur into a pattern of alternating fast- and slow-moving streams. A strong argument for a magnetic origin of the observed variability would be the detection of a long-term stellar activity cycle. Evidence is presented, based on Mg II spectra acquired between 1982 and 1988, for a long-term change in the mean wind velocity of AB Aur and in its velocity amplitude. As yet there is no proof the changes are part of a long-term activity cycle. Such evidence should be sought over the remaining lifetime of IUE in order to constrain existing theories of stellar dynamos.
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