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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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