Stellar magnetic cycles

Abstract

The solar activity cycle is a manifestation of the hydromagnetic dynamo working inside our star. The detection of activity cycles in solar-like stars and the study of their properties allow us to put the solar dynamo in perspective, investigating how dynamo action depends on stellar parameters and stellar structure. Nevertheless, the lack of spatial resolution and the limited time extension of stellar data pose limitations to our understanding of stellar cycles and the possibility to constrain dynamo models. I briefly review some results obtained from disc-integrated proxies of stellar magnetic fields and discuss the new opportunities opened by space-borne photometry, made available by MOST, CoRoT, Kepler, and GAIA, and by new ground-based spectroscopic or spectropolarimetric observations. Stellar cycles have a significant impact on the energetic output and circumstellar magnetic fields of late-type active stars which affects the interaction between stars and their planets. On the other hand, a close-in massive planet could affect the activity of its host star. Recent observations provide circumstantial evidence of such an interaction with possible consequences for stellar activity cycles.

10 pages, Invited paper at the IAU Symposium 264, held during the 2009 IAU General Assembly in Rio de Janeiro, Brasil, from 3 to 7 August 2009; Editors: A. H. Andrei, A. G. Kosovichev and J.-P. Rozelot

References in corpus (7)

• The case for a distributed solar dynamo shaped by near-surface shear
• Patterns of photometric and chromospheric variation among Sun-like stars: A 20-year perspective
• Magnetic cycles of the planet-hosting star Tau Bootis: II. a second magnetic polarity reversal
• Butterfly Diagram and Activity Cycles in HR 1099
• Photospheric and Subphotospheric Dynamics of Emerging Magnetic Flux
• Sounding stellar cycles with Kepler - I. Strategy for selecting targets
• Star-Planet Interactions

Cited by in corpus (4)

• Asteroseismology of solar-type stars
• Unsigned magnetic flux proxy from solar optical intensity spectra
• The impact of rotation on the stochastic excitation of stellar acoustic modes in solar-like pulsators
• Simulating starspot activity jitter for spectral types F--M: realistic estimates for a representative sample of known exoplanet hosts