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Related papers: Center-to-limb Variations in Solar Plage using IRI…

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The center-to-limb variations (CLV) of Gaussian fit parameters of the transition region Si~{\sc iv} 1402.77~{\AA} spectral line in quiet Sun (QS) and coronal hole (CH) regions are presented. The results are derived from a full-disk mosaic…

Solar and Stellar Astrophysics · Physics 2023-09-13 Pradeep Kayshap , Peter R. Young

We study the non-thermal velocities in the quiet-sun using various high spatial, temporal, and spectral resolution observations from the Interface Region Imaging Spectrograph (IRIS). We focus our analysis on the transition region using the…

Solar and Stellar Astrophysics · Physics 2022-01-26 Yamini K. Rao , Giulio Del Zanna , Helen E. Mason

It is generally accepted that densities of quiet sun and active region plasma are sufficiently low to justify the optically thin approximation, and it is commonly used in the analysis of line emissions from plasma in the solar corona.…

Solar and Stellar Astrophysics · Physics 2018-02-14 Edward Thiemann , Phillip Chamberlin , Francis Eparvier , Luke Epp

Studying Doppler shifts provides deeper insights into the flow of mass and energy in the solar atmosphere. We perform a comprehensive measurement of Doppler shifts in the transition region and its center-to-limb variation (CLV) in the…

Solar and Stellar Astrophysics · Physics 2023-03-01 Abhishek Rajhans , Durgesh Tripathi , Vinay L. Kashyap , James A. Klimchuk , Avyarthana Ghosh

The Sun's spectrum varies with center-to-limb distance. This variation is governed by the underlying temperature-density structure of the solar atmosphere. To explore the spectrally resolved center-to-limb variation (CLV) we make use of two…

Solar and Stellar Astrophysics · Physics 2014-12-24 Jan Stenflo

We present high-resolution spectroscopic observations of the quiet-Sun center-to-limb variations (CLV) of the He I triplet at 10 830 {\AA} and the nearby Si I 10 827 {\AA} line, observed with GREGOR Infrared Spectrograph (GRIS) and the…

Solar and Stellar Astrophysics · Physics 2026-01-16 A. G. M. Pietrow , C. Kuckein , M. Verma , C. Denker , J. C. Trelles Arjona , R. Kamlah , K. Poppenhäger

Stellar photospheric inhomogeneities are a significant source of noise which currently precludes the discovery of Earth-mass planets orbiting Sun-like stars with the radial-velocity (RV) method. To complement several previous studies which…

Solar and Stellar Astrophysics · Physics 2024-04-26 Michael L. Palumbo , Steven H. Saar , Raphaëlle D. Haywood

Granular convective motions reach into the lower solar atmosphere, typically causing photospheric spectral lines to exhibit a differential line shift. This Doppler shift to shorter wavelength is commonly known as convective blueshift. We…

Solar and Stellar Astrophysics · Physics 2019-01-30 Franziska Stief , Johannes Löhner-Böttcher , Wolfgang Schmidt , Tilo Steinmetz , Ronald Holzwarth

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

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

Convective motions in the solar atmosphere cause spectral lines to become asymmetric and shifted in wavelength. For photospheric lines, this differential Doppler shift varies from the solar disk center to the limb. Precise and comprehensive…

Solar and Stellar Astrophysics · Physics 2019-04-10 Johannes Löhner-Böttcher , Wolfgang Schmidt , Rolf Schlichenmaier , Tilo Steinmetz , Ronald Holzwarth

We present constraints on the structure of the chromosphere from observations of the Ca II H line profile near and off the solar limb. We obtained a data set of the Ca II H line in a field of view extending 20" across the limb. We analyzed…

Solar and Stellar Astrophysics · Physics 2015-05-28 C. Beck , R. Rezaei

An accurate description of the center-to-limb variation (CLV) of stellar spectra is becoming an increasingly critical factor in both stellar and exoplanet characterization. In particular, the CLV of spectral lines is extremely challenging…

Solar and Stellar Astrophysics · Physics 2024-12-25 Alexander G. M. Pietrow , Adur Pastor Yabar

We measured the center-to-limb variation of the brightness temperature, $T_b$, from ALMA full-disk images at two frequencies and inverted the solution of the transfer equation to obtain the electron temperature, $T_e$ as a function of…

Solar and Stellar Astrophysics · Physics 2017-09-13 C. E. Alissandrakis , S. Patsourakos , A. Nindos , T. S. Bastian

The observed center-to-limb variation (CLV) of the scattering polarization in different lines of the Second Solar Spectrum can be used to constrain the height variation of various atmospheric parameters, in particular the magnetic fields…

Solar and Stellar Astrophysics · Physics 2015-06-22 H. D. Supriya , H. N. Smitha , K. N. Nagendra , J. O. Stenflo , M. Bianda , R. Ramelli , B. Ravindra , L. S. Anusha

We present the first results of sunspot oscillations from observations by the Interface Region Imaging Spectrograph. The strongly nonlinear oscillation is identified in both the slit-jaw images and the spectra of several emission lines…

The center-to-limb variation (CLV) describes the brightness of the stellar disk as a function of the limb angle. Across strong absorption lines, the CLV can vary quite significantly. We obtained a densely sampled time series of…

Solar and Stellar Astrophysics · Physics 2015-10-14 S. Czesla , T. Klocová , S. Khalafinejad , U. Wolter , J. H. M. M. Schmitt

Observations of center-to-limb variations (CLV) of spectral lines and continua provide a good test for the accuracy of models of solar and stellar atmospheric structure and spectral-line formation. They are also widely used to constrain…

Solar and Stellar Astrophysics · Physics 2023-03-22 A. G. M. Pietrow , D. Kiselman , O. Andriienko , D. J. M. Petit dit de la Roche , C. J. Díaz Baso , F. Calvo

A comprehensive understanding of the structure of Doppler motions in transition region including the center-to-limb variation and its relationship with the magnetic field structure is vital for the understanding of mass and energy transfer…

Solar and Stellar Astrophysics · Physics 2020-01-08 Avyarthana Ghosh , James A. Klimchuk , Durgesh Tripathi

The convective motions of solar granules generate a center-to-limb variation of Doppler velocity in the photospheric lines, known as the limb shift effect. This study presents a comprehensive analysis of this effect for the Fe I 6569 {\AA}…

Solar and Stellar Astrophysics · Physics 2026-02-05 H. C. Yu , M. D. Ding , J. Hong , Y. K. Wang , Z. Li
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