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Related papers: Long-term Evolution of the Solar Corona Using PROB…

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The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle. We aim to determine a number of sunspot…

Solar and Stellar Astrophysics · Physics 2011-08-23 Fraser T. Watson , Lyndsay Fletcher , Stephen Marshall

The global structure of solar corona observed in optical window is governed by the global magnetic field with different characteristics over solar activity cycle. Ludendorff flattening index becomes a popular measure of the global structure…

Solar and Stellar Astrophysics · Physics 2016-12-14 Rhorom Priyatikanto

The X-ray emission from the Sun reveals a very dynamic hot atmosphere, the corona, which is characterized by a complex morphology and broad range of timescales of variability and spatial structuring. The solar magnetic fields play a…

Solar and Stellar Astrophysics · Physics 2022-06-09 Paola Testa , Fabio Reale

The goal of this paper is to study the smallest brightening events observed in the EUV quiet Sun. We use commissioning data taken by the EUI instrument onboard the recently launched Solar Orbiter mission. On 2020 May 30, EUI was situated at…

Context. Extreme ultraviolet (EUV) late-phase (ELP) flares exhibit a second peak in warm coronal emissions minutes to hours after the main peak of the flare. This phase is all but negligible, and it is still poorly understood what role it…

Solar and Stellar Astrophysics · Physics 2025-12-02 Sascha Ornig , Astrid M. Veronig , Karin Dissauer

We present observations and analysis of an X1.8 non-eruptive solar flare on 2012 October 23, which is characterized by an extremely large late-phase peak seen in the warm coronal extreme-ultraviolet (EUV) emissions ($\sim$ 3 MK), with the…

Solar and Stellar Astrophysics · Physics 2024-10-25 Shihan Li , Yu Dai , Mingde Ding , Jinhan Guo , Hao Wu

The solar corona is host to a continuous flow of propagating disturbances (PD). These are continuous and ubiquitous across broad regions of the corona, including the quiet Sun. The aim of this paper is to present an improved, efficient…

Solar and Stellar Astrophysics · Physics 2022-08-31 Huw Morgan , Marianna Korsos

Relativistically blurred reflection from the accretion disc provides a powerful probe of the extreme environments close to supermassive black holes; the inner regions of the accretion flow and the corona that produces the intense X-ray…

High Energy Astrophysical Phenomena · Physics 2015-11-05 D. R. Wilkins

Coronal active regions are studied using Hinode/EIS observations in the EUV line Fe XII {\lambda}195.12 by analyzing their line profiles from 2006 December to 2019 December. The period covers the last 2 yr of solar cycle 23 and solar cycle…

Solar and Stellar Astrophysics · Physics 2022-05-24 Maya Prabhakar , K. P Raju

The heating of coronal loops is investigated to understand the observational consequences in terms of the thermodynamics and radiative losses from the Sun as well as the magnetized coronae of stars with an outer convective envelope. The…

Solar and Stellar Astrophysics · Physics 2018-07-02 A. F. Rappazzo , R. B. Dahlburg , G. Einaudi , M. Velli

The existence of the million-degree corona above the cooler photosphere is an unsolved problem in astrophysics. Detailed study of quiescent corona that exists regardless of the phase of the solar cycle may provide fruitful hints towards…

Solar and Stellar Astrophysics · Physics 2022-12-07 Vishal Upendran , Durgesh Tripathi , N. P. S. Mithun , Santosh Vadawale , Anil Bhardwaj

We analyze the variability of the spectral solar irradiance during the period from 7 January, 2010 until 20 January, 2010 as measured by the Herzberg channel (190-222 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA2. In this period…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 A. V. Shapiro , A. I. Shapiro , M. Dominique , I. E. Dammasch , C. Wehrli , E. Rozanov , W. Schmutz

We use X-ray observations of the nearby binaries 61 Cyg A/B (K5V and K7V) and Alpha Cen A/B (G2V and K1V) to study the long-term evolution of magnetic activity in weakly to moderately active G + K dwarfs over nearly a decade. Specifically…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. Robrade , J. H. M. M. Schmitt , F. Favata

Coronal condensation and rain are a crucial part of the mass cycle between the corona and chromosphere. In some cases, condensation and subsequent rain originate in the magnetic dips formed during magnetic reconnection. This provides a new…

Solar and Stellar Astrophysics · Physics 2021-04-07 Leping Li , Hardi Peter , Lakshmi Pradeep Chitta , Hongqiang Song

We use images of high spatial, spectral and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the coupling between wave phenomena observed at numerous heights in the solar atmosphere. Intensity…

Solar and Stellar Astrophysics · Physics 2015-06-11 D. B. Jess , I. De Moortel , M. Mathioudakis , D. J. Christian , K. P. Reardon , P. H. Keys , F. P. Keenan

This paper reports on the re-analysis of solar flares in which the hard X-rays (HXRs) come predominantly from the corona rather than from the more usual chromospheric footpoints. All of the 26 previously analyzed event time intervals, over…

Solar and Stellar Astrophysics · Physics 2018-11-07 Brian R. Dennis , Miguel A. Duval-Poo , Michele Piana , Andrew R. Inglis , A. Gordon Emslie , Jingnan Guo , Yan Xu

Solar flares typically have an impulsive phase that followed by a gradual phase as best seen in soft X-ray emissions. A recent discovery based on the EUV Variability Experiment (EVE) observations onboard the Solar Dynamics Observatory (SDO)…

Solar and Stellar Astrophysics · Physics 2015-04-22 Kai Liu , Jie Zhang , Yuming Wang , Xin Cheng

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

Coronal rain is the most dramatic cooling phenomenon of the solar corona and an essential diagnostic tool for the coronal heating properties. A puzzling feature of the solar corona, besides the heating, is its EUV filamentary structure and…