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Stellar activity cycles: observing the dynamo?
The enormous complexity of the atmospheric structure observed on the Sunmakes it very difficult to compare the Sun with ``solar-type stars''.Clearly, we need to identify parameters that can be observed on the Sunas well as on other stars which can be interpreted unambiguously. Themost widely accepted dynamo signature is the presence of an activitycycle, well documented for the Sun and for main-sequence stars due tothe Mount Wilson Ca II H&K project. Only recently have we detectedspatial information, differential rotation and possibly meridional flowson other stars and thereby adding another constraint for itsinterpretation within a dynamo theory. Again, the picture is notcomplete yet, despite that there is just a single main ingredient thatacts as the driving mechanism for activity in all atmospheric layers andthe convective envelope of a solar-type star: the dynamo-relatedmagnetic field. I stress the importance of mapping stellar surfaces asfingerprints of the underlying dynamo action over long periods of time.
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Datos observacionales y astrométricos
| Constelación: | Ballena |
| Ascensión Recta: | 01h42m10.37s |
| Declinación: | +02°18'28.9" |
| Magnitud Aparente: | 7.512 |
| Distancia: | 125.471 parsecs |
| Movimiento Propio en Ascensión Recta: | -5.1 |
| Movimiento Propio en Declinación: | 13 |
| B-T magnitude: | 7.749 |
| V-T magnitude: | 7.532 |
Catálogos y designaciones:
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