Characteristics of sunspot longitudinal distribution and their correlation with solar activity in pre-Greenwich data

Иванов, В. П.; Miletsky, E. V.

doi:10.1134/s0016793216070082

“…These values indicate that the spot size increases with increasing latitude. This tendency is similar to the sunspot property that the cycleintegrated sunspot area is positively correlated with the mean latitude Solanki et al 2008;Ivanov & Miletsky 2016). Although the A-type binaries also show a similar association at least below λ ∼ 60 • (rp = −0.415 with p = 0.110 and rs = −0.356 with p = 0.175 in the range 30 • < θ < 90 • , and rp =0.334 with p = 0.191 and rs =0.430 with p = 0.085 in the range 90 • < θ < 150 • ), these correlations are weaker than those of the W-type sample.…”

Section: Positionsupporting

confidence: 73%

Starspots in contact and semi-detached binary systems

Kouzuma

¹

2019

Publications of the Astronomical Society of Japan

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We investigated the statistical properties of both cool and hot starspots in eclipsing binary stars. The starspot and binary parameters for contact and semi-detached systems were collected from literature, which were determined on the basis of synthetic light-curve analysis. We examined associations between these parameters. As a result, the cool spots in W-type binaries show properties similar to those of sunspots and starspots generated by dynamos, which differs from those of the cool spots in A-type binaries. The properties of hot spots also differ between the W-and A-type samples. From the physical properties of A-and W-type binaries, we infer that mass transfer is a dominant process for forming the hot spots in A-type binaries; and both mass transfer and magnetic activity can contribute to the formation of the hot spots in W-type binaries. Our results also indicate that the hot-spot size in the A-type sample is correlated with the temperature of spotted stars, orbital period, mass ratio, and fill-out factor.

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“…Finally, Solanki et al (2008) have computed various moments of sunspot distribution, separately for two hemispheres, and have shown that the three lowest moments (i.e, the total area covered by the sunspots over a cycle, the mean sunspot latitudes, and the width of the distribution) are well correlated with each other. Recently, Ivanov & Miletsky (2016) showed that the latitude properties of sunspot distribution are much more stable against the gaps of observations and hence these properties can be used for estimates of quality of observations and for data series calibration.…”

Section: Introductionmentioning

confidence: 99%

Latitude Distribution of Sunspots: Analysis Using Sunspot Data and a Dynamo Model

Mandal

¹

,

Karak

²

,

Banerjee

³

2017

ApJ

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In this paper, we explore the evolution of sunspot latitude distribution and explore its relations with the cycle strength. With the progress of the solar cycle the distributions in two hemispheres from mid-latitudes propagate toward the equator and then (before the usual solar minimum) these two distributions touch each other. By visualizing the evolution of the distributions in two hemispheres, we separate the solar cycles by excluding this hemispheric overlap. From these isolated solar cycles in two hemispheres, we generate latitude distributions for each cycle, starting from cycle 8 to cycle 23. We find that the parameters of these distributions, namely, the central latitude (C), width (δ) and height (H) evolve with the cycle number and they show some hemispheric asymmetries. Although the asymmetries in these parameters persist for a few successive cycles, they get corrected within a few cycles and the new asymmetries appear again. In agreement with the previous study, we find that distribution parameters are correlated with the strengths of the cycles, although these correlations are significantly different in two hemispheres. The general trend that stronger cycles begin sunspot eruptions at relatively higher latitudes and have wider bands of sunspot emergence latitudes are confirmed when combining the data from two hemispheres. We explore these features using a flux transport dynamo model with stochastic fluctuations. We find that these features are correctly reproduced in this model. The solar cycle evolution of the distribution center is also in good agreement with observations. Possible explanations of the observed features based on this dynamo model are presented.

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“…These sources include information not only on numbers, but also on heliolatitudes of sunspots. As we showed in [3,4], there is a high correlation between the latitude dispersions of sunspots and power of solar activity. Therefore, we can made independent estimates of the activity level in this epoch.…”

Section: Introductionmentioning

confidence: 59%

“…

Two important sources of information about sunspots in the Maunder minimum are the Spörer catalog [1] and observations of the Paris observatory [2], which cover in total the last quarter of the 17th and the first two decades of the 18th century.These data, in particular, contain information about sunspot latitudes. As we showed in [3,4], dispersions of sunspot latitude distributions are tightly related to sunspot indices, so we can estimate the level of solar activity in this epoch by a method which is not based on direct calculation of sunspots and is weakly affected by loss of observational data.The latitude distributions of sunspots in the time of transition from the Maunder minimum to the common regime of solar activity proved to be wide enough. It gives evidences in favor of, first, not very low cycle No.

…”

mentioning

confidence: 99%

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Latitude and Power Characteristics of Solar Activity at the End of the Maunder Minimum

Иванов

¹

,

Miletsky

²

2017

Geomagn. Aeron.

Self Cite

1

0

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Two important sources of information about sunspots in the Maunder minimum are the Spörer catalog [1] and observations of the Paris observatory [2], which cover in total the last quarter of the 17th and the first two decades of the 18th century.These data, in particular, contain information about sunspot latitudes. As we showed in [3,4], dispersions of sunspot latitude distributions are tightly related to sunspot indices, so we can estimate the level of solar activity in this epoch by a method which is not based on direct calculation of sunspots and is weakly affected by loss of observational data.The latitude distributions of sunspots in the time of transition from the Maunder minimum to the common regime of solar activity proved to be wide enough. It gives evidences in favor of, first, not very low cycle No. −3 (1712-1723) with the Wolf number in maximum W = 100 ± 50, and, second, nonzero activity in the maximum of cycle No. −4 (1700-1711) W = 60 ± 45.Therefore, the latitude distributions in the end of the Maunder minimum are in better agreement with the traditional Wolf number and new revisited indices of activity SN and GN [5,6] than with the GSN [7]; the latter provide much lower level of activity in this epoch.

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Characteristics of sunspot longitudinal distribution and their correlation with solar activity in pre-Greenwich data

Cited by 3 publications

References 8 publications

Starspots in contact and semi-detached binary systems

Starspots in contact and semi-detached binary systems

Latitude Distribution of Sunspots: Analysis Using Sunspot Data and a Dynamo Model

Latitude and Power Characteristics of Solar Activity at the End of the Maunder Minimum

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