Flip-flop phenomenon: observations and theory

Abstract

In many active stars the spots concentrate on two permanent active longitudes which are 180 degrees apart. In some of these stars the dominant part of the spot activity changes the longitude every few years. This so-called flip-flop phenomenon has up to now been reported in 11 stars, both single and binary alike, and including also the Sun. To explain this phenomenon, a non-axisymmetric dynamo mode, giving rise to two permanent active longitudes at opposite stellar hemispheres, is needed together with an oscillating axisymmetric magnetic field. Here we discuss the observed characteristics of the flip-flop phenomenon and present a dynamo solution to explain them.

4 pages, 5 figures, contribution to the conference "Dynamos of the Sun, Stars and Planets", to be published in AN Volume 326

References in corpus (3)

• Doin' the twist: Secular changes in the surface differential rotation on AB Doradus
• The first close-up of the "flip-flop" phenomenon in a single star
• Do spherical alpha^2-dynamos oscillate?

Cited by in corpus (20)

• On the role of meridional flows in flux transport dynamo models
• The Magnetic Topology of the Weak-Lined T Tauri Star V410 - A Simultaneous Temperature and Magnetic Field Inversion
• Magnetic field topology of the RS CVn star II Pegasi
• Spots, plages, and flares on lambda Andromedae and II Pegasi
• Forward modelling of brightness variations in Sun-like stars I. Emergence and surface transport of magnetic flux
• Starspots, Stellar Cycles and Stellar Flares: Lessons from Solar Dynamo Models
• Spot evolution on the red giant star XX Triangulum. A starspot-decay analysis based on time-series Doppler imaging
• Multiperiodicity, modulations and flip-flops in variable star light curves II. Analysis of II Peg photometry during 1979-2010
• Investigating variation of latitudinal stellar spot rotation and its relation to the real stellar surface rotation
• Effects of large-scale non-axisymmetric perturbations in the mean-field solar dynamo
• Time-series Doppler imaging of the red giant HD 208472. Active longitudes and differential rotation
• Observing dynamos in cool stars
• Magnetic activity of the young solar analogue V1358 Ori
• LO Peg: surface differential rotation, flares, and spot-topographic evolution
• Magnetic Structure of Rapidly Rotating FK Comae-Type Coronae
• Long-term photometry of three active red giants in close binary systems: V2253 Oph, IT Com and IS Vir
• AstroGrid-D: Grid Technology for Astronomical Science
• Scattering linear polarization of late-type active stars
• Magnetic field evolution in solar-type stars
• Data-driven stabilizations of goodness-of-fit tests