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Related papers: Solar limb faculae: intensity contrast from two va…

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"Weak" magnetic-field diagnostics in faint objects near the bright solar disk are discussed in terms of the level of non-object signatures, in particular, of the stray light in telescopes. Calculated dependencies of the stray light caused…

Solar and Stellar Astrophysics · Physics 2013-11-20 I. S. Kim , I. V. Alexeeva , O. I. Bugaenko , V. V. Popov , E. Z. Suyunova

Most observations of the solar corona beyond 2 Rs consist of broadband visible light imagery from coronagraphs. The associated diagnostics mainly consist of kinematics and derivations of the electron number density. While the measurement of…

Solar and Stellar Astrophysics · Physics 2023-06-28 Auchère , F. , Berghmans , D. , Dumesnil , C. , Halain , J. -P. , Mercier , R. , Rochus , P. , Delmotte , F. , François , S. , Hermans , A. , Hervier , V. , Kraaikamp , E. , Meltchakov , E. , Morinaud , G. , Philippon , A. , Smith , P. J. , Stegen , K. , Verbeeck , C. , Zhang , X. Y. , Andretta , V. , Abbo , L. , Buchlin , E. , Frassati , F. , Gissot , S. , Gyo , M. , Harra , L. , Jerse , G. , Landini , F. , Mierla , M. , Nicula , B. , Parenti , S. , Renotte , E. , Romoli , M. , Russano , G. , Sasso , C. , Schühle , U. , Schmutz , W. , Soubrié , E. , Susino , R. , Teriaca , L. , West , M. , Zhukov , A. N

Microturbulence (\xi) is a key parameter introduced in stellar spectroscopy to explain the strength of saturated lines by formally incorporating an additional thermal broadening term in the line opacity profile. Although our Sun can serve…

Solar and Stellar Astrophysics · Physics 2022-01-12 Yoichi Takeda

The equivalent widths (W) of 565 spectral lines in the wavelength range of 4690--6870A were evaluated at 31 consecutive points from the solar disk center (mu=cos(theta)=1) to near the limb (mu=0.25) by applying the synthetic…

Solar and Stellar Astrophysics · Physics 2019-06-12 Y. Takeda , S. UeNo

Aims. We use high-resolution spectropolarimetric observations in the Ca ii 8542 A line obtained with the SST to study the magnetic field in solar spicules. Methods. The equations that result from the application of the Weak Field…

Solar and Stellar Astrophysics · Physics 2020-10-07 M. Kriginsky , R. Oliver , N. Freij , D. Kuridze , A. Asensio Ramos , P. Antolin

Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1-m Solar Telescope, we aim to understand how spicules…

Solar and Stellar Astrophysics · Physics 2016-06-22 Tiago M. D. Pereira , Luc Rouppe van der Voort , Mats Carlsson

Solar convection is visible as a net blueshift of absorption lines, which becomes apparent when observing quiet Sun granulation. This blueshift exhibits variations from the disc centre to the solar limb due to differing projection angles…

Solar and Stellar Astrophysics · Physics 2023-12-13 M. Ellwarth , B. Ehmann , S. Schäfer , A. Reiners

Two methods are used to observationally determine the solar radius: One is the observation of the intensity profile at the limb, the other one uses f-mode frequencies to derive a 'seismic' solar radius which is then corrected to optical…

Astrophysics · Physics 2009-11-13 Margit Haberreiter , Alexander G. Kosovichev , Werner Schmutz

For many years, there seemed to be significant differences between the continuum intensity distributions derived from observations and simulations of the solar photosphere. In order to settle the discussion on these apparent discrepancies,…

Solar and Stellar Astrophysics · Physics 2009-08-27 S. Wedemeyer-Böhm , L. Rouppe van der Voort

We present a dataset of high resolution spectra of the Sun of many strongly polarized lines belonging to the second solar spectrum, i.e. the spectrum near the limb in linear polarization (scattering polarization). These solar spectra were…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Jean-Marie Malherbe

CONTEXT: The quiet Sun magnetic fields produce ubiquitous bright points (BPs) that cover a significant fraction of the solar surface. Their contribution to the total solar irradiance (TSI) is so-far unknown. AIMS: To measure the…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. A. Bonet , I. Cabello , J. Sanchez Almeida

The contrast of granulation is an important quantity characterizing solar surface convection. We compare the intensity contrast at 630 nm, observed using the Spectro-Polarimeter (SP) aboard the Hinode satellite, with the 3D radiative MHD…

A dense forest of slender bright fibrils near a small solar active region is seen in high-quality narrowband Ca II H images from the SuFI instrument onboard the Sunrise balloon-borne solar observatory. The orientation of these slender Ca II…

The surface brightness fluctuations (SBF) method measures the variance in a galaxy's light distribution arising from fluctuations in the numbers and luminosities of individual stars per resolution element. Once calibrated for stellar…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-06 John Blakeslee

Solar surface magneto-convection appears as granulation pattern that impacts spectral lines in terms of both shape and wavelength. Such induced effects also tend to vary over the observed solar disc because of the changing observation angle…

Solar and Stellar Astrophysics · Physics 2023-05-03 M. Ellwarth , S. Schäfer , A. Reiners , M. Zechmeister

Solar-Limb Effect is an observational phenomena connected to the solar gravitational red-shift. It shows a variation of the magnitude of the gravitational red-shift from the center to the limb of the solar disc. In the present work an…

General Relativity and Quantum Cosmology · Physics 2010-08-06 M. I. Wanas , A. B. Morcos , S. I. El Gammal

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

We study Doppler velocity measurements at multiple heights in the solar atmosphere using a set of six filtergrams obtained by the Helioseismic magnetic Imager on board the Solar Dynamics Observatory. There are clear and significant phase…

Solar and Stellar Astrophysics · Physics 2014-01-15 Kaori Nagashima , Laurent Gizon , Aaron Birch , Björn Löptien , Sebastien Couvidat , Bernhard Fleck

Consecutive height series of Ha spectra in solar limb spicules taken on the 53 cm coronagraph of Abastumani Astrophysical Observatory at the heights of 3800-8700 km above the photosphere have been analyzed. The aim is to observe oscillatory…

Astrophysics · Physics 2009-11-13 T. V. Zaqarashvili , E. Khutsishvili , V. Kukhianidze , G. Ramishvili