An Analysis of the Solar Differential Rotation in Solar Cycle No. 19 (1954 – 1964) Determined Using Kanzelhöhe Sunspot Group Positions

IF 2.4 3区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Solar Physics Pub Date : 2025-08-22 DOI:10.1007/s11207-025-02528-7

Ivana Poljančić Beljan, Luka Šibenik, Tomislav Jurkić, Klaudija Lončarić, Rajka Jurdana-Šepić, Damir Hržina, Werner Pötzi, Roman Brajša, Astrid M. Veronig, Arnold Hanslmeier

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Abstract

We study solar differential rotation for solar cycle No. 19 (1954 – 1964) by tracing sunspot groups on the sunspot drawings of Kanzelhöhe Observatory for Solar and Environmental Research (KSO). Our aim is to extend previous differential rotation (DR) analysis from the KSO data (1964 – 2016) to the years prior to 1964 to create a catalog of sunspot group positions and photospheric DR parameters from KSO sunspot drawings and white light images. Synodic angular rotation velocities were first determined using the daily shift (DS) and robust linear least-squares fit (rLSQ) methods, then converted to sidereal velocities, and subsequently used to derive solar DR parameters. We compare the DR parameters obtained from different sources and analyse the north–south asymmetry of rotation for solar cycle No. 19. It has been shown that our results for the equatorial rotation velocity (parameter \(A\)) and the gradient of DR (parameter \(B\)) coincide with earlier results from the KSO data (performed with a different method), as well as with results from the Kodaikanal Solar Observatory (KoSO) and the Yunnan Observatories (YNAO). In contrast, the values of parameter \(A\) from three different earlier studies based on the Greenwich Photoheliographic Results (GPR) exhibit statistically significant differences when compared to the values of parameter \(A\) derived from KSO, KoSO and YNAO. These findings suggest that the GPR data have the largest inconsistency compared to the other three data sources, highlighting the need for further analysis to identify the causes of these discrepancies. The analysis of the north-south asymmetry in the solar rotation profile using two different methods shows that the DR parameters of the hemispheres coincide, indicating a rotational symmetry around the equator. This is consistent with previous results from KSO and YNAO data. However, all sources indicate slightly higher equatorial rotation velocities in the southern hemisphere.

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利用Kanzelhöhe太阳黑子群位置分析第19太阳周期（1954 - 1964）的太阳微分旋转

本文通过在Kanzelhöhe太阳与环境研究天文台（KSO）的太阳黑子图上追踪太阳黑子群，研究了第19太阳周期（1954 - 1964）的太阳微分旋转。我们的目标是将以前的微分旋转（DR）分析从KSO数据（1964 - 2016）扩展到1964年之前的年份，从KSO太阳黑子图和白光图像中创建太阳黑子群位置和光球DR参数目录。首先使用日移（DS）和鲁棒线性最小二乘拟合（rLSQ）方法确定了视点角转速，然后将其转换为恒星速度，随后用于推导太阳DR参数。我们比较了不同来源的DR参数，并分析了第19太阳周期的南北旋转不对称性。结果表明，赤道自转速度（参数\(A\)）和DR梯度（参数\(B\)）与KSO数据（采用不同的方法）以及Kodaikanal太阳观测台（KoSO）和云南天文台（YNAO）的结果一致。相比之下，基于格林尼greenwich photohelographic Results （GPR）的三个不同早期研究的参数\(A\)的值与来自KSO、KoSO和YNAO的参数\(A\)的值相比，具有统计学上的显著差异。这些发现表明，与其他三个数据源相比，探地雷达数据存在最大的不一致性，突出表明需要进一步分析以确定这些差异的原因。用两种不同的方法对太阳自转剖面的南北不对称性进行了分析，结果表明，半球的DR参数重合，表明在赤道周围存在旋转对称性。这与以前KSO和YNAO数据的结果一致。然而，所有的资料都表明南半球的赤道旋转速度略高。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Solar Physics 地学天文-天文与天体物理

CiteScore

5.10

自引率

17.90%

发文量

146

审稿时长

1 months

期刊介绍： Solar Physics was founded in 1967 and is the principal journal for the publication of the results of fundamental research on the Sun. The journal treats all aspects of solar physics, ranging from the internal structure of the Sun and its evolution to the outer corona and solar wind in interplanetary space. Papers on solar-terrestrial physics and on stellar research are also published when their results have a direct bearing on our understanding of the Sun.