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Related papers: Using Polar Faculae to Determine the Sun's High-La…

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In a previous paper, I described a new way of determining the high-latitude solar rotation rate statistically from space-time maps of polar faculae observed in the 6767 \r{A} continuum by the Michelson Doppler Interferometer (MDI) on the…

Solar and Stellar Astrophysics · Physics 2025-02-04 Neil R. Sheeley

The rotation of sunspots of 2 yr in two different solar cycles is studied with the data from the Helioseismic and Magnetic Imager on board the \it Solar Dynamics Observatory \rm and the Michelson Doppler Imager instrument on board the \it…

Solar and Stellar Astrophysics · Physics 2016-07-29 Jianchuan Zheng , Zhiliang Yang , Kaiming Guo , Haimin Wang , Shuo Wang

For the period of 1997-2006, coronal holes detected in the SOHO/EIT 195 $\AA$ full disk calibrated images are used to compute the rotation rates of high latitude and near polar coronal holes and, their latitudinal variation is investigated.…

Solar and Stellar Astrophysics · Physics 2022-04-12 K. M. Hiremath , Manjunath Hegde , K. R. Varsha

Polar faculae are bright features that can be detected in solar limb observations and they are related to magnetic field concentrations. Although there is a large number of works studying them, some questions about their nature as their…

Solar and Stellar Astrophysics · Physics 2016-05-25 C. Quintero Noda , Y. Suematsu , B. Ruiz Cobo , T. Shimizu , A. Asensio Ramos

Context. The relation between solar surface rotation and sunspot activity still remains open. Sunspot activity has dramatically reduced in solar cycle 24 and several solar activity indices and flux measurements experienced unprecedentedly…

Solar and Stellar Astrophysics · Physics 2015-02-18 L. Zhang , K. Mursula , I. Usoskin

Using the Solar Optical Observing Network (SOON) sunspot-group data for the period 1985-2010, the variations in the annual mean equatorial-rotation rates of the sunspot groups are determined and compared with the known variations in the…

Solar and Stellar Astrophysics · Physics 2013-07-29 J. Javaraiah

Frequency splitting coefficients from Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations covering the period 1995--2001 are used to study temporal variations in the solar rotation rate at high latitudes.…

Astrophysics · Physics 2009-11-07 H. M. Antia , Sarbani Basu

The analysis of the rotation rate of individual sunspots and pores was performed according to the data of the processing of observations by the \textit{Solar Dynamics Observatory/Helioseismic and Magnetic Imager} (SDO/HMI) in the period…

Solar and Stellar Astrophysics · Physics 2024-11-12 Andrei G. Tlatov , Kseniia A. Tlatova

Understanding the global rotational profile of the solar atmosphere and its variation is fundamental to uncovering a comprehensive understanding of the dynamics of the solar magnetic field and the extent of coupling between different layers…

For the years 2001-2008, we use full-disk, SOHO/EIT 195 $\AA$ calibrated images to determine latitudinal and day to day variations of the rotation rates of coronal holes. We estimate the weighted average of heliographic coordinates such as…

Solar and Stellar Astrophysics · Physics 2015-06-12 K. M. Hiremath , M. Hegde

Oscillation properties in two sunspots and two facular regions are studied using Solar Dynamics Observatory (SDO) data and ground-based observations in the SiI 10827 and HeI 10830 lines. The aim is to study different-frequency spatial…

Solar and Stellar Astrophysics · Physics 2014-11-25 N. I. Kobanov , D. Y. Kolobov , A. A. Chelpanov

The aim of this paper is to study the latitudinal variation in the solar rotation in soft X-ray corona. The time series bins are formed on different latitude regions of the solar full disk (SFD) images that extend from 80 degree South to 80…

Solar and Stellar Astrophysics · Physics 2015-05-18 Satish Chandra , Hari Om Vats , K. N. Iyer

Rotation of the large scale solar magnetic field has a great importance for the understanding of solar dynamic, for the search of longitidinal structure and for the study of solar-terrestrial relations. 30-year long observations taken at…

Solar and Stellar Astrophysics · Physics 2018-02-08 E. A. Gavryuseva

A new set of accurately measured frequencies of solar oscillations are used to infer the rotation rate inside the Sun, as a function of radial distance as well as latitude. We have adopted a regularized least squares technique with…

Astrophysics · Physics 2009-10-30 H. M. Antia , Sarbani Basu , S. M. Chitre

The present paper discusses results of a statistical study of the characteristics of coronal hole (CH) rotation in order to find connections to the internal rotation of the Sun. The goal is to measure CH rotation rates and study their…

Systematic studies of the rotation rate of sunspot groups using white-light images yield controversial results on the variations of the rotation rate: sunspot groups were found to either accelerate or decelerate systematically. This…

Solar and Stellar Astrophysics · Physics 2023-01-18 Alexander S. Kutsenko , Valentina I. Abramenko , Daria V. Litvishko

The solar images at 17 GHz by Nobeyama Radio Heliograph and in X-ray by soft X-ray telescope (SXT) on board Yohkoh satellite have been of particular interest for the estimation of solar coronal rotation using flux modulation approach. These…

Solar and Stellar Astrophysics · Physics 2015-05-27 Hari Om Vats , Satish Chandra

Over 54 years of hourly mean value of solar wind velocity from 27 Nov. 1963 to 31 Dec. 2017 are used to investigate characteristics of the rotation period of solar wind through auto-correlation analysis. Solar wind of high velocity is found…

Solar and Stellar Astrophysics · Physics 2019-09-25 Kejun Li , W. Feng

On the Sun, the rotation periods of individual sunspots not only trace the latitude dependence of the surface rotation rate, but also provide clues as to the amount of subsurface fluid shear. In this paper we present the first measurements…

Astrophysics · Physics 2009-11-07 A. Collier Cameron , J. -F. Donati , M. Semel

The global rotational profile of the solar atmosphere and its variation at different layers, although crucial for a comprehensive understanding of the dynamics of the solar magnetic field, has been a subject to contradictory results…

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