The sector structure of the active longitudes in solar cycles

Mikhailutsa, V. P.; Makarova, V. V.

doi:10.1007/bf00680602

“…There are many peaks at twice the normal value and one, in cycle 18 at 85°-90°, at three times the normal value. Some of these peaks persist from one cycle to the next, a result that has been noted by many authors including Balthasar and Schuessler (1983), Bumba and Henja (1991), Miklailutsa and Makarova (1994), and Bai (2003). Henney and Harvey (2002) noted the persistence of magnetic structures in the northern hemisphere at preferred longitudes (drifting slightly due to the latitude) for two decades but also noted that the sunspot records suggests that two decades is about the limit of such persistence (as seen in Figure 36b).…”

Section: Active Longitudessupporting

confidence: 56%

The Solar Cycle

Hathaway

¹

2010

Living Rev. Sol. Phys.

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The Solar Cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. We examine a number of other solar activity indicators including the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores that vary in association with the sunspots. We examine the characteristics of individual solar cycles including their maxima and minima, cycle periods and amplitudes, cycle shape, and the nature of active latitudes, hemispheres, and longitudes. We examine long-term variability including the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev-Ohl Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double peaked maxima. We conclude with an examination of prediction techniques for the solar cycle.

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“…There are many peaks at twice the normal value and one, in cycle 18 at 85°-90°, at three times the normal value. Some of these peaks even appear to persist from one cycle to the next, a result that has been noted by many authors including Bumba and Henja (1991), Miklailutsa and Makarova (1994), and Bai (2003). Henney and Harvey (2002) noted the persistence of magnetic structures in the northern hemisphere at preferred longitudes (drifting slightly due to the latitude) for two decades but also noted that (as seen in Figure 32b) that the sunspot records suggests that two decades is about the limit of such persistence.…”

Section: Active Longitudesmentioning

confidence: 69%

The Solar Cycle

Hathaway

¹

2010

Living Rev. Sol. Phys.

View full text Add to dashboard Cite

The Solar Cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. We examine a number of other solar activity indicators including the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores that vary in association with the sunspots. We examine the characteristics of individual solar cycles including their maxima and minima, cycle periods and amplitudes, cycle shape, and the nature of active latitudes, hemispheres, and longitudes. We examine long-term variability including the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev-Ohl Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double peaked maxima. We conclude with an examination of prediction techniques for the solar cycle.

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“…In the present Sun, only weak traces of this mode were observed as shortlived active longitudes (e.g. Bumba & Howard 1965;Vitinskij 1969;Mikhailutsa & Makarova 1994) or preferred hemispheres (Balthasar & Schüssler 1984).…”

Section: How Does the Stellar Dynamo Evolve?mentioning

confidence: 70%

Magnetic activity in the young solar analog LQ Hydrae

Berdyugina

¹

,

Pelt

²

,

Tuominen

³

2002

A&A

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Abstract. We present the first evidence that a single active dwarf of solar type can show a long-lived, nonaxisymmetric spot distribution -active longitudes on opposite hemispheres, similar to evolved, rapidly rotating RS CVn-type binary stars. We analyse new as well as published photometric observations of the young active dwarf LQ Hya, spanning almost 20 years. We find that activity of the star has three activity cycles: a 5.2-yr "flip-flop" cycle, a 7.7-yr period in the amplitude modulation of the brightness and an approximately 15-yr period in variations of the mean brightness. The two shorter cycles are related to the alternating active longitudes and are similar to cycles observed in RS CVn-type stars. The 15-yr cycle reflects periodic changes of the mean spottedness of the star and resembles the solar 11-year cycle. The spot rotation period (about 1.6 days) changes during the 15-yr cycle, indicating the presence of small differential rotation. The lengths of the three cycles are related as 3:2:1, with the repetition of the spot configuration after 15 years. We discuss the possibility that the observed spot cycles represent two different magnetic dynamo modes operating in LQ Hya: an axisymmetric mode, as in the Sun, and a nonaxisymmetric higher order mode with two cycles in spot patterns. Our results suggest that young stars exhibit their cycles in spot distribution, as seen in LQ Hya. This is in contrast to the conclusion based on the analysis of Ca  H&K emission from plages. The results suggest also that the Vaughan-Preston gap represents a transition from a multiple-mode dynamo to a single-mode dynamo.

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The sector structure of the active longitudes in solar cycles

Cited by 15 publications

References 9 publications

The Solar Cycle

The Solar Cycle

The Solar Cycle

Magnetic activity in the young solar analog LQ Hydrae

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