Differential Rotation of Solar Filaments Early Observed by the OGAUC in the Period 1929 – 1941

Wan, Miao; Li, Kejun

doi:10.1007/s11207-022-02059-5

Cited by 6 publications

(9 citation statements)

References 50 publications

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“…In addition, we discussed the correlation between the rotation rate and the solar activity represented by the yearly mean total sunspot numbers, and found the rotation rate of the STR follows the overall trend as solar activity, which supports the results reported by Japaridze & Chargeishvili (2016), Sharma et al (2021), Wan & Gao (2022), and Wan & Li (2022). In the comparison of the rotational coefficients, we found the STR rotates more slowly and more rigidly than the solar chromosphere and the corona.…”

Section: Discussionsupporting

confidence: 87%

“…These behaviors suggest that the rotation rate of the STR follows the same trend as solar activity and is modulated by the solar cycle as well. Some authors have reported the Sun rotates faster during the solar cycle maxima by analyzing different data sets (Japaridze & Chargeishvili 2016;Sharma et al 2021;Wan & Gao 2022;Wan & Li 2022), and our finding is in agreement with their results. Especially for the result of Sharma et al (2021), who studied the rotation of the STR as well.…”

Section: Cycle-related Variations Of the Rotation Rate And Solar Acti...supporting

confidence: 93%

“…It is widely confirmed that the Sun exhibits differential rotation, meaning the Sun rotates fastest at the equator, and its rotation rate decreases with increasing latitudes. The solar rotation rate as a function of latitude can be described by the following traditional formula (Newton & Nunn 1951;Pulkkinen & Tuominen 1998a, 1998bWan & Li 2022):…”

Section: Methodsmentioning

confidence: 99%

“…Li et al (2020) found the high chromosphere rotates faster than the photosphere by investigating synoptic maps of He I intensity. Wan & Li (2022) reported the chromosphere filaments rotate faster than sunspots, the photosphere, and the medium-low chromosphere at middlelow latitudes. Chandra et al (2009) reported the solar corona rotates less differentially than the photosphere and chromosphere by investigating solar full disk (SFD) images of Nobeyama Radioheliograph (NoRH) at 17 GHz.…”

Section: Introductionmentioning

confidence: 99%

“…Sharma et al (2021) presented the average solar rotation rate follows the trend of solar activity by investigating SFD images at 30.4 nm wavelength observed from STEREO (2008STEREO ( -2018. Wan & Li (2022) obtained the rotation profile as ( ) ( ) 14.914 0.263 w f =  -( ) 3.505 0.684 sin 2 f  , and found the solar filaments rotate at a higher rotation rate in the descending phase of the solar cycle than in the ascending phase by using the daily Ca II K3 observations. Therefore, the dependence of the solar rotation rate on the solar cycle phase is not clear and needs further study.…”

Section: Introductionmentioning

confidence: 99%

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Rotational Characteristics of the Solar Transition Region Using SDO/AIA 304 Å Images

Wu,

Zheng,

Zeng

et al. 2023

ApJ

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To date, the rotational characteristics of the solar transition region remain unclear. In this work, by applying the flux modulation method to the images derived from the Solar Dynamics Observatory/Atmospheric Imaging Assembly between 2011 and 2022 at 304 Å wavelength, we have studied the rotation of the solar transition region, and the results obtained are as follows. The solar transition region rotates differentially, while, from the perspective of the entire time interval, the rotation coefficients A and B are 14.39 (±0.08) and −1.61 (±0.15), respectively, and we find no prominent asymmetry in the average rotation rate of the northern and southern hemispheres. The solar transition region rotates fastest during the solar cycle maximum, and the average rotation rate follows the overall trend of solar activity. Both the equatorial rotation rate (represented by coefficient A) and the latitudinal gradient (represented by coefficient B) of the solar transition region are smaller than that of the solar chromosphere and the corona, indicating the solar transition region rotates more slowly and more rigidly than the other two layers, and we speculate that the solar chromosphere and corona seem to restrain the rotation of the solar transition region at the same time.

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Section: Discussionsupporting

confidence: 87%

Section: Cycle-related Variations Of the Rotation Rate And Solar Acti...supporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Rotational Characteristics of the Solar Transition Region Using SDO/AIA 304 Å Images

Wu,

Zheng,

Zeng

et al. 2023

ApJ

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A Comparison of Various Observational Results of Solar Differential Rotation

Brajša,

Hanslmeier

2024

UNITEXT for Physics

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Analysis of full-disc Hαobservations: Carrington maps and filament properties in 1909–2022

Chatzistergos,

Ermolli,

Banerjee

et al. 2023

A&A

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Context.Full-disc observations of the Sun in the Hαline provide information about the solar chromosphere, and in particular, about the filaments, which are dark and elongated features that lie along magnetic field polarity-inversion lines. This makes them important for studies of solar magnetism. Because full-disc Hαobservations have been performed at various sites since the second half of the 19th century, with regular photographic data having started at the beginning of the 20th century, they are an invaluable source of information on past solar magnetism.Aims.We derive accurate information about filaments from historical and modern full-disc Hαobservations.Methods.We consistently processed observations from 15 Hαarchives spanning 1909–2022. The analysed datasets include long-running ones such as those from Meudon and Kodaikanal, but also previously unexplored datasets such as those from Arcetri, Boulder, Larissa, and Upice. Our data processing includes photometric calibration of the data stored on photographic plates, the compensation for limb-darkening, and the orientation of the data to align solar north at the top of the images. We also constructed Carrington maps from the calibrated Hαimages.Results.We find that filament areas, similar to plage areas in Ca IIK data, are affected by the bandwidth of the observation. Thus, a cross calibration of the filament areas derived from different archives is needed. We produced a composite of filament areas from individual archives by scaling all of them to the Meudon series. Our composite butterfly diagram very distinctly shows the common features of filament evolution, that is, the poleward migration as well as a decrease in the mean latitude of filaments as the cycle progresses. We also find that during activity maxima, filaments cover ∼1% of the solar surface on average. The change in the amplitude of cycles in filament areas is weaker than in sunspot and plage areas.Conclusions.Analysis of Hαdata for archives with contemporaneous Ca IIK observations allowed us to identify and verify archive inconsistencies, which also have implications for reconstructions of past solar magnetism and irradiance from Ca IIK data.

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Differential Rotation of Solar Filaments Early Observed by the OGAUC in the Period 1929 – 1941

Cited by 6 publications

References 50 publications

Rotational Characteristics of the Solar Transition Region Using SDO/AIA 304 Å Images

Rotational Characteristics of the Solar Transition Region Using SDO/AIA 304 Å Images

A Comparison of Various Observational Results of Solar Differential Rotation

Analysis of full-disc Hαobservations: Carrington maps and filament properties in 1909–2022

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