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Multi-instrument data sets of NOAA AR10938 on Jan. 16, 2007, (e.g., {\emph{Hinode}}, {\it{STEREO}}, {\it{GOES}}, {\it{MLSO}} and {\it{ISOON}} H$\alpha$) are utilized to study the fine structure and evolution of a magnetic loop system…

Solar and Stellar Astrophysics · Physics 2009-11-13 N. -E. Raouafi

Flare ribbons form when energy released by coronal magnetic reconnection is deposited in the low solar atmosphere, so by studying the dynamics of flare ribbons, one obtains an indirect measurement of reconnection. Our aim is to quantify the…

Solar and Stellar Astrophysics · Physics 2026-05-13 Hannah Collier , Säm Krucker , Laura A. Hayes , Emil Kraaikamp , David Berghmans , Daniel F. Ryan

The structure and evolution of close binary stars has been studied using the two-dimensional (2D) stellar structure algorithm developed by Deupree (1995). We have calculated a series of solar composition stellar evolution sequences of…

Astrophysics · Physics 2009-11-13 R. G. Deupree , A. I. Karakas

Extracting the temperature of coronal loops is effective in the analysis of solar active region's loops and helps in better understanding of coronal events. To this end, various methods have already been developed like the method developed…

Solar and Stellar Astrophysics · Physics 2019-08-30 Narges Fathalian

Many low-mass pre-main-sequence stars exhibit strong magnetic activity and coronal X-ray emission. Even after the primordial accretion disk has been cleared out, the star's high-energy radiation continues to affect the formation and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Steven R. Cranmer , David J. Wilner , Meredith A. MacGregor

SDO/EVE provides rich information of the thermodynamic processes of solar activities, particularly of solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could…

Solar and Stellar Astrophysics · Physics 2016-03-11 Yuming Wang , Zhenjun Zhou , Jie Zhang , Kai Liu , Rui Liu , Chenglong Shen , Phillip C. Chamberlin

Stellar flares are characterized by sudden enhancement of electromagnetic radiation from the atmospheres of stars. Compared to their solar counterparts, our knowledge on the coronal plasma dynamics of stellar flares and their connection to…

Solar and Stellar Astrophysics · Physics 2022-07-20 Hechao Chen , Hui Tian , Hao Li , Jianguo Wang , Hongpeng Lu , Yu Xu , Zhenyong Hou , Yuchuan Wu

Magnetic tornadoes, characterized as impulsive Alfven waves initiated by photospheric vortices in intergranular lanes, are considered efficient energy channels to the corona. Despite their acknowledged importance for solar coronal heating,…

Solar and Stellar Astrophysics · Physics 2024-07-03 Hidetaka Kuniyoshi , Souvik Bose , Takaaki Yokoyama

We present a first systematic study on the cross-sectional temperature structure of coronal loops using the six coronal temperature filters of the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO). We…

Solar and Stellar Astrophysics · Physics 2015-05-27 Markus J. Aschwanden , Paul Boerner

Studying chromospheric activity of contact binaries is an important way of revealing the magnetic activity processes of these systems. An efficient but somewhat neglected method for that is to follow the changes of the H$\alpha$ line…

Solar and Stellar Astrophysics · Physics 2020-03-18 T. Mitnyan , T. Szalai , A. Bódi , L. Kriskovics , K. Vida , B. Cseh , O. Hanyecz , A. Ordasi , A. Pál , J. Vinkó

If magnetic activity in outer stellar atmospheres is due to an interplay between rotation and subsurface convection, as is generally presumed, then one would not expect to observe indicators of activity in stars with T_eff > 8300 K. Any…

Astrophysics · Physics 2009-11-13 J. E. Neff , T. Simon

We present first results of a novel technique that provides, for the first time, constraints on the energy input flux at the coronal base ($r\sim\,1.025\,{\rm R}_\odot$) of the quiet-Sun at a global scale. By combining differential emission…

Solar and Stellar Astrophysics · Physics 2017-07-19 C. Mac Cormack , A. M. Vásquez , M. López Fuentes , F. A. Nuevo , E. Landi , R. A. Frazin

Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the…

Solar and Stellar Astrophysics · Physics 2015-06-17 Michael B. Kennedy , Ryan O. Milligan , Mihalis Mathioudakis , Francis P. Keenan

We present a new model for the coronal structure of rapidly rotating solar-type stars. The presence of prominences trapped in co-rotation 2 to 5 stellar radii above the stellar surface has been taken as evidence that the coronae of these…

Astrophysics · Physics 2009-11-11 M. Jardine , A. A. van Ballegooijen

An analysis of Lyman series lines arising from hydrogen-like oxygen and neon ions in the coronae of the active RS CVn-type binaries II Peg and IM Peg, observed using the {\it Chandra} High Resolution Transmission Grating Spectrograph, shows…

Astrophysics · Physics 2009-11-10 Paola Testa , Jeremy J. Drake , Giovanni Peres , Edward E. DeLuca

Evidence from the analysis of eclipsing binary systems revealed that late-type stars are larger and cooler than predicted by models, and that this is probably caused by stellar magnetic activity. In this work, we revisit this problem taking…

Solar and Stellar Astrophysics · Physics 2022-12-13 J. C. Morales , I. Ribas , Á. Giménez , D. Baroch

We have explored the magnetic flux evolution and temperature variation in a coronal-hole region, using Big Bear Solar Observatory (BBSO) deep magnetograms and {\it SOHO}/EIT images observed from 2005 October 10 to 14. For comparison, we…

Astrophysics · Physics 2010-11-11 Jun Zhang , Guiping Zhou , Jingxiu Wang , Haimin Wang

Observations from the NASA Solar Dynamic Observatory Atmospheric Imaging Assembly were employed to investigate targeted physical properties of coronal active region structures across the entirety of Solar Cycle 24 (dates). This is the…

Solar and Stellar Astrophysics · Physics 2023-05-19 Daniel Gordon Gass , Robert William Walsh

There is currently no explanation of why the corona has the temperature and density it has. We present a model which explains how the dynamics of magnetic reconnection regulates the conditions in the corona. A bifurcation in magnetic…

Astrophysics · Physics 2009-11-13 P. A. Cassak , D. J. Mullan , M. A. Shay

We present an investigation of the Extreme-Ultraviolet (EUV) wave linked to the flare that occurred on 28 October 2021, along with the associated coronal loop oscillation and type II radio burst. The EUV wave was observed by multi-viewpoint…

Solar and Stellar Astrophysics · Physics 2025-07-03 Pooja Devi , Ramesh Chandra , Arun Kumar Awasthi , Brigitte Schmieder , Reetika Joshi