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This white paper is a call for a concerted effort to support total solar eclipse observations over the next decade, in particular for the 21 August 2017 eclipse which will traverse the US continent. With the recent advances in image…

Solar and Stellar Astrophysics · Physics 2015-03-19 Shadia R. Habbal , John Cooper , Adrian Daw , Adalbert Ding , Miloslav Druckmuller , Ruth Esser , Judd Johnson , Huw Morgan

(abridged) We investigate the long-term evolution of X-ray coronae of solar analogs based on high-resolution X-ray spectroscopy and photometry with XMM-Newton. Six nearby main-sequence G stars with ages between ~0.1 Gyr and \~1.6 Gyr and…

Astrophysics · Physics 2009-11-10 A. Telleschi , M. Guedel , K. Briggs , M. Audard , J. -U. Ness , S. L. Skinner

This paper is a follow up of the article where Lemaire and Stegen (2016) introduced their DYN method to calculate coronal temperature profiles from given radial distributions of the coronal and solar wind (SW) electron densities. Several…

Solar and Stellar Astrophysics · Physics 2021-04-21 Joseph F. Lemaire , Athanassios C. Katsiyannis

Why the tenuous solar outer atmosphere, or corona, is much hotter than the underlying layers remains one of the greatest challenge for solar modeling. Detailed diagnostics of the coronal thermal structure come from extreme ultraviolet (EUV)…

Solar and Stellar Astrophysics · Physics 2018-05-02 Gregory Fleishman , Sophie Musset , Véronique Bommier , Lindsay Glesener

The Airborne Infrared Spectrometer (AIR-Spec) offers an unprecedented opportunity to explore the Near Infra-Red (NIR) wavelength range. It has been flown at two total solar eclipses, in 2017 and 2019. The wavelength range of the much…

Solar and Stellar Astrophysics · Physics 2023-03-01 G. Del Zanna , J. Samra , A. Monaghan , C. Madsen , P. Bryans , E. DeLuca , H. Mason , B. Berkey , A. de Wijn , Y. Rivera

We review our state of knowledge of coronal element abundance anomalies in the Sun and stars. We concentrate on the first ionization potential (FIP) effect observed in the solar corona and slow-speed wind, and in the coronae of solar-like…

Solar and Stellar Astrophysics · Physics 2015-09-30 J. Martin Laming

The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…

Solar and Stellar Astrophysics · Physics 2023-05-17 Yingjie Zhu , Judit Szente , Enrico Landi

The quiet solar corona emits meter-wave thermal bremsstrahlung. Coronal radio emission can only propagate above that radius, $R_\omega$, where the local plasma frequency eqals the observing frequency. The radio interferometer LOw Frequency…

Solar and Stellar Astrophysics · Physics 2018-06-13 C. Vocks , G. Mann , F. Breitling , M. M. Bisi , B. Dabrowski , R. Fallows , P. T. Gallagher , A. Krankowski , J. Magdalenic , C. Marque , D. Morosan , H. Rucker

On 2019 July 2 a total solar eclipse -- visible across some parts of the Southern Pacific Ocean, Chile and Argentina -- will enable observations of the Sun's large-scale coronal structure. The structure of the Sun's corona and their…

Solar and Stellar Astrophysics · Physics 2021-09-01 Soumyaranjan Dash , Prantika Bhowmik , Athira B S , Nirmalya Ghosh , Dibyendu Nandy

The solar corona is a template to understand stellar activity. The Sun is a moderately active star, and its corona differs from active stars: active stellar coronae have a double-peaked EM(T) with the hot peak at 8-20 MK, while the non…

Astrophysics · Physics 2009-11-13 C. Argiroffi , G. Peres , S. Orlando , F. Reale

We investigate the iron K$\alpha$ fluorescent line produced by hard X-ray photons from magnetic reconnection-heated corona. The hot corona with temperature being about $10^9$K can irradiate the underlying disk with a continuum X-ray…

Astrophysics · Physics 2009-11-13 N. Kawanaka , S. Mineshige , K. Iwasawa

Total solar eclipses (TSEs) provide a unique opportunity to quantify the properties of the K-corona (electrons), F-corona (dust) and E-corona (ions) continuously from the solar surface out to a few solar radii. We apply a novel inversion…

Solar and Stellar Astrophysics · Physics 2021-05-12 Benjamin Boe , Shadia Habbal , Cooper Downs , Miloslav Druckmuller

During solar flares, a large fraction of the released magnetic energy is carried by energetic electrons that transfer and deposit energy in the Sun's atmosphere. Electron transport is often approximated by a cold thick-target model (CTTM),…

Solar and Stellar Astrophysics · Physics 2019-08-09 Natasha L. S. Jeffrey , Eduard P. Kontar , Lyndsay Fletcher

Elements with low First Ionization Potential (FIP) are known to be three to four times more abundant in active region loops of the solar corona than in the photosphere. There have been observations suggesting that this observed "FIP bias"…

Cool, dense material is frequently observed to permeate the hot, tenuous solar corona in the form of prominences, spicules and coronal rain. Both the cool material and surrounding corona exist at temperatures that are effectively thermally…

Solar and Stellar Astrophysics · Physics 2026-01-30 B. Snow , A. Hillier

We present a measurement of the abundance of Fe relative to H in the solar corona using a technique which differs from previous spectroscopic and solar wind measurements. Our method combines EUV line data from the CDS spectrometer on SOHO…

Astrophysics · Physics 2016-08-30 S. M. White , R. J. Thomas , J. W. Brosius , M. R. Kundu

Solar eruptive phenomena, like flares and coronal mass ejections(CMEs) are governed by magnetic fields. To describe the structure of these phenomena one needs information on the magnetic flux density and the electric current density vector…

Solar and Stellar Astrophysics · Physics 2015-06-17 Tilaye Tadesse , T. Wiegelmann , Pevtsov A Alexei , P. Macneice , S. Gosain

Visible and near-infrared (V+NIR) emission lines were the first to be discovered in the corona, during total solar eclipses, and they continue to offer unique opportunities to study the physical properties of the corona. The most commonly…

Instrumentation and Methods for Astrophysics · Physics 2023-02-24 Benjamin Boe , Shadia Habbal , Adalbert Ding

I characterize the global distribution of the 3/4 keV band background with a simple model of the hot Galactic corona, plus an isotropic extragalactic background. The corona is assumed to be approximately polytropic (index = 5/3) and…

Astrophysics · Physics 2009-10-30 Q. Daniel Wang

Solar corona, the last main layer of the atmosphere of the Sun, is detectable in the EUV and X-ray. The corona is expanding into space up to millions of kilometers and is observable during the eclipse. The temperature is increasing about…

Solar and Stellar Astrophysics · Physics 2019-04-02 Najmeh Ahmadi , Shervin Parsi