English
Related papers

Related papers: Spatial Inhomogeneity In Solar Faculae

200 papers

This work focus on the first results on the identification and characterization of periodic plasma density fluctuations in the outer corona, observed in STEREO-A COR1 white-light image time series. A 2D reconstruction of the spatial…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. Telloni , R. Ventura , P. Romano , D. Spadaro , E. Antonucci

Small-scale magnetic flux concentrations contribute significantly to the brightness variations of the Sun, yet observing them - particularly their magnetic field - near the solar limb remains challenging. Solar Orbiter offers an…

Solar and Stellar Astrophysics · Physics 2026-02-11 K. Albert , J. Hirzberger , N. A. Krivova , X. Li , D. Calchetti , G. Valori , J. Sinjan , S. K. Solanki , A. Gandorfer , J. Woch , D. Orozco Suárez , S. Parenti

The latitudinal sound-speed structure of the Sun's convection zone gives insight into the physical processes occurring there, specifically the cellular convection and possibly the presence of magnetic fields. Using helioseismic data from…

Astrophysics · Physics 2008-11-26 H. M. Antia , S. M. Chitre , M. J. Thompson

Solar activity has a cyclic nature with the ~11-year Schwabe cycle dominating its variability on the interannual timescale. However, solar cycles are significantly modulated in length, shape and magnitude, from near-spotless grand minima to…

Solar and Stellar Astrophysics · Physics 2023-03-29 Akash Biswas , Bidya Karak , Ilya Usoskin , Eckhard Weisshaar

This paper describes a new way of determining the high-latitude solar rotation rate statistically from simultaneous observations of many polar faculae. In this experiment, I extracted frames from a movie made previously from flat-fielded…

Solar and Stellar Astrophysics · Physics 2024-11-05 Neil R. Sheeley

The Sun and stars with low magnetic activity levels, become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behaviour and get fainter when their activity increases. We reproduce…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. I. Shapiro , S. K. Solanki , N. A. Krivova , W. K. Schmutz , W. T. Ball , R. Knaack , E. V. Rozanov , Y. C. Unruh

The physics of solar flares occurring on the Sun is highly complex and far from fully understood. However, observations show that solar eruptions are associated with the intense kilogauss fields of active regions, where free energies are…

Solar and Stellar Astrophysics · Physics 2024-01-26 Bach Viet Do , Yang Chen , XuanLong Nguyen , Ward Manchester

Magnetic features on the surfaces of cool stars cause variations of their brightness. Such variations have been extensively studied for the Sun. Recent planet-hunting space telescopes allowed measuring brightness variations in hundred…

Solar and Stellar Astrophysics · Physics 2020-04-15 N. -E. Nèmec , A. I. Shapiro , N. A. Krivova , S. K. Solanki , R. V. Tagirov , R. H. Cameron , S. Dreizler

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a time scale of several solar cycles whose origin and properties are currently debated. This paper addresses the question of whether the…

Solar and Stellar Astrophysics · Physics 2019-05-08 Alexander Nepomnyashchikh , Sudip Mandal , Dipankar Banerjee , Leonid Kitchatinov

We analyse the spatial distribution of current helicity in solar active regions. A comparison of current helicity maps derived from three different instruments (Helioseismic and Magnetc Imager on board the Solar Dynamics Observatory,…

Solar and Stellar Astrophysics · Physics 2018-08-15 A. S. Kutsenko , V. I. Abramenko , K. M. Kuzanyan , Haiqing Xu , Hongqi Zhang

The precise shape of the Sun is sensitive to the influence of gravity, differential rotation, local turbulence and magnetic fields. It has been previously shown that the solar shape exhibits asphericity that evolves with the 11-year cycle.…

Solar and Stellar Astrophysics · Physics 2018-08-15 A. G. Kosovichev , J. -P. Rozelot

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…

Solar and Stellar Astrophysics · Physics 2017-12-27 Sudip Mandal , Bidya Binay Karak , Dipankar Banerjee

Recent models of variations of the Sun's structure with the 11-year activity cycle by Sofia et al (2005) predict strong non-homologous changes of the radius of subsurface layers, due to subsurface magnetic fields and field-modulated…

Astrophysics · Physics 2009-11-13 S. Lefebvre , A. G. Kosovichev , J. P. Rozelot

We aim to gain insight into the effect of network and faculae on solar irradiance from their apparent intensity. Taking full-disc observations from the Solar Dynamics Observatory, we examined the intensity contrast of network and faculae in…

Solar and Stellar Astrophysics · Physics 2021-02-19 K. L. Yeo , N. A. Krivova

The aim of this paper is to investigate the spatial structure of the impulsive phase hard X-ray emission from solar flares. This work is motivated by the YOHKOH and the forthcoming HESSI observations. Summarizing past results, it is shown…

Astrophysics · Physics 2009-10-31 Vahe Petrosian , Timothy Q. Donaghy

Surfaces of the Sun and other cool stars are filled with magnetic fields, which are either seen as dark compact spots or more diffuse bright structures like faculae. Both hamper detection and characterisation of exoplanets, affecting…

Solar and Stellar Astrophysics · Physics 2022-08-03 N. -E. Nèmec , A. I. Shapiro , E. Işık , K. Sowmya , S. K. Solanki , N. A. Krivova , R. H. Cameron , L. Gizon

In recent years solar oscillations have been studied in great detail, both observationally and theoretically; so, perhaps, the Sun currently is the best understood pulsating star. The observational studies include long, almost uninterrupted…

Solar and Stellar Astrophysics · Physics 2010-02-01 A. G. Kosovichev

Recent analyses of the helioseismic observations indicate that the previously observed surface torsional oscillations with periods of about 11 years extend significantly downwards into the solar convective zone. Furthermore, there are…

Astrophysics · Physics 2007-05-23 Eurico Covas , Reza Tavakol , David Moss

For the first time, a multi-wave research of oscillation dynamics in a solar facula from its birth to decay was carried out. We performed spectral observations of active region NOAA 12744 at Horizontal Solar Telescope of the Sayan Solar…

Solar and Stellar Astrophysics · Physics 2020-08-26 Andrei Chelpanov , Nikolai Kobanov